diff --git a/src/DataGrid.tsx b/src/DataGrid.tsx
index 71ee3dc72a..2affb2fb1a 100644
--- a/src/DataGrid.tsx
+++ b/src/DataGrid.tsx
@@ -22,8 +22,10 @@ import {
   createCellEvent,
   getCellStyle,
   getColSpan,
+  getColumnInColumns,
   getLeftRightKey,
   getNextSelectedCellPosition,
+  getRowInRows,
   isCtrlKeyHeldDown,
   isDefaultCellInput,
   isSelectedCellEditable,
@@ -360,6 +362,9 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
     enableVirtualization
   });
 
+  /**
+   * computed values
+   */
   const topSummaryRowsCount = topSummaryRows?.length ?? 0;
   const bottomSummaryRowsCount = bottomSummaryRows?.length ?? 0;
   const summaryRowsCount = topSummaryRowsCount + bottomSummaryRowsCount;
@@ -368,15 +373,9 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
   const minRowIdx = -headerAndTopSummaryRowsCount;
   const mainHeaderRowIdx = minRowIdx + groupedColumnHeaderRowsCount;
   const maxRowIdx = rows.length + bottomSummaryRowsCount - 1;
-
-  const [selectedPosition, setSelectedPosition] = useState(
-    (): SelectCellState | EditCellState<R> => ({ idx: -1, rowIdx: minRowIdx - 1, mode: 'SELECT' })
-  );
-
-  /**
-   * computed values
-   */
+  const maxColIdx = columns.length - 1;
   const isTreeGrid = role === 'treegrid';
+  const minColIdx = isTreeGrid ? -1 : 0;
   const headerRowsHeight = headerRowsCount * headerRowHeight;
   const summaryRowsHeight = summaryRowsCount * summaryRowHeight;
   const clientHeight = gridHeight - headerRowsHeight - summaryRowsHeight;
@@ -384,6 +383,30 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
   const { leftKey, rightKey } = getLeftRightKey(direction);
   const ariaRowCount = rawAriaRowCount ?? headerRowsCount + rows.length + summaryRowsCount;
 
+  let [selectedPosition, setSelectedPosition] = useState(
+    (): SelectCellState | EditCellState<R> => ({ idx: -1, rowIdx: minRowIdx - 1, mode: 'SELECT' })
+  );
+
+  // Reinitialize the position and immediately use the new state
+  // if the current values are no longer valid.
+  // This can happen if a column or row is removed.
+  if (
+    !(
+      selectedPosition.idx === -1 &&
+      selectedPosition.rowIdx === minRowIdx - 1 &&
+      selectedPosition.mode === 'SELECT'
+    ) &&
+    (selectedPosition.idx < minColIdx ||
+      selectedPosition.idx > maxColIdx ||
+      selectedPosition.rowIdx < minRowIdx ||
+      selectedPosition.rowIdx > maxRowIdx)
+  ) {
+    selectedPosition = { idx: -1, rowIdx: minRowIdx - 1, mode: 'SELECT' };
+    // eslint-disable-next-line sonarjs/no-useless-react-setstate
+    setSelectedPosition(selectedPosition);
+    setDraggedOverRowIdx(undefined);
+  }
+
   const defaultGridComponents = useMemo(
     () => ({
       renderCheckbox,
@@ -457,8 +480,6 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
     setIsColumnResizing
   );
 
-  const minColIdx = isTreeGrid ? -1 : 0;
-  const maxColIdx = columns.length - 1;
   const selectedCellIsWithinSelectionBounds = isCellWithinSelectionBounds(selectedPosition);
   const selectedCellIsWithinViewportBounds = isCellWithinViewportBounds(selectedPosition);
 
@@ -561,7 +582,7 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
     ) {
       const step = sign(rowIdx - previousRowIdx);
       for (let i = previousRowIdx + step; i < rowIdx; i += step) {
-        const row = rows[i];
+        const row = getRow(i);
         if (isRowSelectionDisabled?.(row) === true) continue;
         if (checked) {
           newSelectedRows.add(rowKeyGetter(row));
@@ -579,12 +600,11 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
     if (mode === 'EDIT') return;
 
     if (onCellKeyDown && isRowIdxWithinViewportBounds(rowIdx)) {
-      const row = rows[rowIdx];
       const cellEvent = createCellEvent(event);
       onCellKeyDown(
         {
           mode: 'SELECT',
-          row,
+          row: getRow(rowIdx),
           column: columns[idx],
           rowIdx,
           selectCell
@@ -633,7 +653,7 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
 
   function updateRow(column: CalculatedColumn<R, SR>, rowIdx: number, row: R) {
     if (typeof onRowsChange !== 'function') return;
-    if (row === rows[rowIdx]) return;
+    if (row === getRow(rowIdx)) return;
     const updatedRows = rows.with(rowIdx, row);
     onRowsChange(updatedRows, {
       indexes: [rowIdx],
@@ -643,29 +663,38 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
 
   function commitEditorChanges() {
     if (selectedPosition.mode !== 'EDIT') return;
-    updateRow(columns[selectedPosition.idx], selectedPosition.rowIdx, selectedPosition.row);
+    updateRow(getColumn(selectedPosition.idx), selectedPosition.rowIdx, selectedPosition.row);
   }
 
   function handleCellCopy(event: CellClipboardEvent) {
-    if (!selectedCellIsWithinViewportBounds) return;
+    if (!selectedCellIsWithinViewportBounds || typeof onCellCopy !== 'function') return;
+
     const { idx, rowIdx } = selectedPosition;
-    onCellCopy?.({ row: rows[rowIdx], column: columns[idx] }, event);
+
+    // Prevent copy/paste on group rows
+    if (idx === -1) return;
+
+    onCellCopy({ row: getRow(rowIdx), column: getColumn(idx) }, event);
   }
 
   function handleCellPaste(event: CellClipboardEvent) {
-    if (!onCellPaste || !onRowsChange || !isCellEditable(selectedPosition)) {
+    if (
+      typeof onCellPaste !== 'function' ||
+      typeof onRowsChange !== 'function' ||
+      !isCellEditable(selectedPosition)
+    ) {
       return;
     }
 
     const { idx, rowIdx } = selectedPosition;
-    const column = columns[idx];
-    const updatedRow = onCellPaste({ row: rows[rowIdx], column }, event);
+    const column = getColumn(idx);
+    const updatedRow = onCellPaste({ row: getRow(rowIdx), column }, event);
     updateRow(column, rowIdx, updatedRow);
   }
 
   function handleCellInput(event: KeyboardEvent<HTMLDivElement>) {
     if (!selectedCellIsWithinViewportBounds) return;
-    const row = rows[selectedPosition.rowIdx];
+    const row = getRow(selectedPosition.rowIdx);
     const { key, shiftKey } = event;
 
     // Select the row on Shift + Space
@@ -752,14 +781,15 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
     if (onRowsChange == null) return;
 
     const { rowIdx, idx } = selectedPosition;
-    const column = columns[idx];
-    const sourceRow = rows[rowIdx];
+    const column = getColumn(idx);
+    const sourceRow = getRow(rowIdx);
     const updatedRows = [...rows];
     const indexes: number[] = [];
     for (let i = startRowIdx; i < endRowIdx; i++) {
       if (isCellEditable({ rowIdx: i, idx })) {
-        const updatedRow = onFill!({ columnKey: column.key, sourceRow, targetRow: rows[i] });
-        if (updatedRow !== rows[i]) {
+        const targetRow = getRow(i);
+        const updatedRow = onFill!({ columnKey: column.key, sourceRow, targetRow });
+        if (updatedRow !== targetRow) {
           updatedRows[i] = updatedRow;
           indexes.push(i);
         }
@@ -774,6 +804,14 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
   /**
    * utils
    */
+  function getColumn(index: number) {
+    return getColumnInColumns(columns, index);
+  }
+
+  function getRow(index: number) {
+    return getRowInRows(rows, index);
+  }
+
   function isColIdxWithinSelectionBounds(idx: number) {
     return idx >= minColIdx && idx <= maxColIdx;
   }
@@ -808,7 +846,7 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
     const samePosition = isSamePosition(selectedPosition, position);
 
     if (options?.enableEditor && isCellEditable(position)) {
-      const row = rows[position.rowIdx];
+      const row = getRow(position.rowIdx);
       setSelectedPosition({ ...position, mode: 'EDIT', row, originalRow: row });
     } else if (samePosition) {
       // Avoid re-renders if the selected cell state is the same
@@ -821,8 +859,8 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
     if (onSelectedCellChange && !samePosition) {
       onSelectedCellChange({
         rowIdx: position.rowIdx,
-        row: isRowIdxWithinViewportBounds(position.rowIdx) ? rows[position.rowIdx] : undefined,
-        column: columns[position.idx]
+        row: isRowIdxWithinViewportBounds(position.rowIdx) ? getRow(position.rowIdx) : undefined,
+        column: getColumn(position.idx)
       });
     }
   }
@@ -952,14 +990,14 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
     }
 
     const { idx, rowIdx } = selectedPosition;
-    const column = columns[idx];
+    const column = getColumn(idx);
     if (column.renderEditCell == null || column.editable === false) {
       return;
     }
 
     const isLastRow = rowIdx === maxRowIdx;
     const columnWidth = getColumnWidth(column);
-    const colSpan = column.colSpan?.({ type: 'ROW', row: rows[rowIdx] }) ?? 1;
+    const colSpan = column.colSpan?.({ type: 'ROW', row: getRow(rowIdx) }) ?? 1;
     const { insetInlineStart, ...style } = getCellStyle(column, colSpan);
     const marginEnd = 'calc(var(--rdg-drag-handle-size) * -0.5 + 1px)';
     const isLastColumn = column.idx + colSpan - 1 === maxColIdx;
@@ -999,7 +1037,7 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
     }
 
     const { idx, row } = selectedPosition;
-    const column = columns[idx];
+    const column = getColumn(idx);
     const colSpan = getColSpan(column, lastFrozenColumnIndex, { type: 'ROW', row });
     const closeOnExternalRowChange = column.editorOptions?.closeOnExternalRowChange ?? true;
 
@@ -1025,7 +1063,7 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
 
     if (
       closeOnExternalRowChange &&
-      rows[selectedPosition.rowIdx] !== selectedPosition.originalRow
+      getRow(selectedPosition.rowIdx) !== selectedPosition.originalRow
     ) {
       // Discard changes if rows are updated from outside
       closeEditor(false);
@@ -1048,7 +1086,7 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
 
   function getRowViewportColumns(rowIdx: number) {
     // idx can be -1 if grouping is enabled
-    const selectedColumn = selectedPosition.idx === -1 ? undefined : columns[selectedPosition.idx];
+    const selectedColumn = columns[selectedPosition.idx];
     if (
       selectedColumn !== undefined &&
       selectedPosition.rowIdx === rowIdx &&
@@ -1086,7 +1124,7 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
       const rowIdx = isRowOutsideViewport ? selectedRowIdx : viewportRowIdx;
 
       let rowColumns = viewportColumns;
-      const selectedColumn = selectedIdx === -1 ? undefined : columns[selectedIdx];
+      const selectedColumn = selectedIdx === -1 ? undefined : getColumn(selectedIdx);
       if (selectedColumn !== undefined) {
         if (isRowOutsideViewport) {
           // if the row is outside the viewport then only render the selected cell
@@ -1097,7 +1135,7 @@ export function DataGrid<R, SR = unknown, K extends Key = Key>(props: DataGridPr
         }
       }
 
-      const row = rows[rowIdx];
+      const row = getRow(rowIdx);
       const gridRowStart = headerAndTopSummaryRowsCount + rowIdx + 1;
       let key: K | number = rowIdx;
       let isRowSelected = false;
diff --git a/src/TreeDataGrid.tsx b/src/TreeDataGrid.tsx
index bafb2e0f10..5c77d858a3 100644
--- a/src/TreeDataGrid.tsx
+++ b/src/TreeDataGrid.tsx
@@ -2,7 +2,7 @@ import { useCallback, useMemo } from 'react';
 import type { Key } from 'react';
 
 import { useLatestFunc } from './hooks';
-import { assertIsValidKeyGetter, getLeftRightKey } from './utils';
+import { assertIsValidKeyGetter, getLeftRightKey, getRowInRows } from './utils';
 import type {
   CellClipboardEvent,
   CellCopyArgs,
@@ -122,7 +122,7 @@ export function TreeDataGrid<R, SR = unknown, K extends Key = Key>({
     ): [Readonly<GroupByDictionary<R>>, number] => {
       let groupRowsCount = 0;
       const groups: GroupByDictionary<R> = {};
-      for (const [key, childRows] of Object.entries(rowGrouper(rows, groupByKey))) {
+      for (const [key, childRows] of Object.entries(rowGrouper(rows, groupByKey!))) {
         // Recursively group each parent group
         const [childGroups, childRowsCount] =
           remainingGroupByKeys.length === 0
@@ -159,7 +159,7 @@ export function TreeDataGrid<R, SR = unknown, K extends Key = Key>({
       Object.keys(rows).forEach((groupKey, posInSet, keys) => {
         const id = groupIdGetter(groupKey, parentId);
         const isExpanded = expandedGroupIds.has(id);
-        const { childRows, childGroups, startRowIndex } = rows[groupKey];
+        const { childRows, childGroups, startRowIndex } = rows[groupKey]!;
 
         const groupRow: GroupRow<R> = {
           id,
@@ -189,6 +189,13 @@ export function TreeDataGrid<R, SR = unknown, K extends Key = Key>({
     }
   }, [expandedGroupIds, groupedRows, rawRows, groupIdGetter]);
 
+  const getRow = useCallback(
+    (index: number) => {
+      return getRowInRows(rows, index);
+    },
+    [rows]
+  );
+
   const rowHeight = useMemo(() => {
     if (typeof rawRowHeight === 'function') {
       return (row: R | GroupRow<R>): number => {
@@ -206,7 +213,7 @@ export function TreeDataGrid<R, SR = unknown, K extends Key = Key>({
     (row: R | GroupRow<R>) => {
       const rowIdx = rows.indexOf(row);
       for (let i = rowIdx - 1; i >= 0; i--) {
-        const parentRow = rows[i];
+        const parentRow = getRow(i);
         if (isGroupRow(parentRow) && (!isGroupRow(row) || row.parentId === parentRow.id)) {
           return [parentRow, i] as const;
         }
@@ -214,7 +221,7 @@ export function TreeDataGrid<R, SR = unknown, K extends Key = Key>({
 
       return undefined;
     },
-    [isGroupRow, rows]
+    [isGroupRow, rows, getRow]
   );
 
   const rowKeyGetter = useCallback(
@@ -299,7 +306,7 @@ export function TreeDataGrid<R, SR = unknown, K extends Key = Key>({
     if (args.mode === 'EDIT') return;
     const { column, rowIdx, selectCell } = args;
     const idx = column?.idx ?? -1;
-    const row = rows[rowIdx];
+    const row = getRow(rowIdx);
 
     if (!isGroupRow(row)) return;
     if (
@@ -347,8 +354,8 @@ export function TreeDataGrid<R, SR = unknown, K extends Key = Key>({
     const updatedRawRows = [...rawRows];
     const rawIndexes: number[] = [];
     for (const index of indexes) {
-      const rawIndex = rawRows.indexOf(rows[index] as R);
-      updatedRawRows[rawIndex] = updatedRows[index];
+      const rawIndex = rawRows.indexOf(getRow(index) as R);
+      updatedRawRows[rawIndex] = getRowInRows(updatedRows, index);
       rawIndexes.push(rawIndex);
     }
     onRowsChange(updatedRawRows, {
diff --git a/src/hooks/useCalculatedColumns.ts b/src/hooks/useCalculatedColumns.ts
index 9929d91a17..afa9ce4658 100644
--- a/src/hooks/useCalculatedColumns.ts
+++ b/src/hooks/useCalculatedColumns.ts
@@ -1,6 +1,6 @@
 import { useMemo } from 'react';
 
-import { clampColumnWidth, max, min } from '../utils';
+import { clampColumnWidth, getColumnInColumns, max, min } from '../utils';
 import type { CalculatedColumn, CalculatedColumnParent, ColumnOrColumnGroup, Omit } from '../types';
 import { renderValue } from '../cellRenderers';
 import { SELECT_COLUMN_KEY } from '../Columns';
@@ -189,14 +189,14 @@ export function useCalculatedColumns<R, SR>({
     }
 
     if (lastFrozenColumnIndex !== -1) {
-      const columnMetric = columnMetrics.get(columns[lastFrozenColumnIndex])!;
+      const columnMetric = columnMetrics.get(getColumnInColumns(columns, lastFrozenColumnIndex))!;
       totalFrozenColumnWidth = columnMetric.left + columnMetric.width;
     }
 
     const layoutCssVars: Record<string, string> = {};
 
     for (let i = 0; i <= lastFrozenColumnIndex; i++) {
-      const column = columns[i];
+      const column = getColumnInColumns(columns, i);
       layoutCssVars[`--rdg-frozen-left-${column.idx}`] = `${columnMetrics.get(column)!.left}px`;
     }
 
@@ -222,7 +222,7 @@ export function useCalculatedColumns<R, SR>({
     // get the first visible non-frozen column index
     let colVisibleStartIdx = firstUnfrozenColumnIdx;
     while (colVisibleStartIdx < lastColIdx) {
-      const { left, width } = columnMetrics.get(columns[colVisibleStartIdx])!;
+      const { left, width } = columnMetrics.get(getColumnInColumns(columns, colVisibleStartIdx))!;
       // if the right side of the columnn is beyond the left side of the available viewport,
       // then it is the first column that's at least partially visible
       if (left + width > viewportLeft) {
@@ -234,7 +234,7 @@ export function useCalculatedColumns<R, SR>({
     // get the last visible non-frozen column index
     let colVisibleEndIdx = colVisibleStartIdx;
     while (colVisibleEndIdx < lastColIdx) {
-      const { left, width } = columnMetrics.get(columns[colVisibleEndIdx])!;
+      const { left, width } = columnMetrics.get(getColumnInColumns(columns, colVisibleEndIdx))!;
       // if the right side of the column is beyond or equal to the right side of the available viewport,
       // then it the last column that's at least partially visible, as the previous column's right side is not beyond the viewport.
       if (left + width >= viewportRight) {
diff --git a/src/hooks/useGridDimensions.ts b/src/hooks/useGridDimensions.ts
index 907d6f02e3..bfeeb7441f 100644
--- a/src/hooks/useGridDimensions.ts
+++ b/src/hooks/useGridDimensions.ts
@@ -19,7 +19,7 @@ export function useGridDimensions() {
     setBlockSize(clientHeight);
 
     const resizeObserver = new ResizeObserver((entries) => {
-      const size = entries[0].contentBoxSize[0];
+      const size = entries[0]!.contentBoxSize[0]!;
 
       // we use flushSync here to avoid flashing scrollbars
       flushSync(() => {
diff --git a/src/hooks/useViewportColumns.ts b/src/hooks/useViewportColumns.ts
index c79d085399..0b4e43677a 100644
--- a/src/hooks/useViewportColumns.ts
+++ b/src/hooks/useViewportColumns.ts
@@ -1,6 +1,6 @@
 import { useMemo } from 'react';
 
-import { getColSpan } from '../utils';
+import { getColSpan, getColumnInColumns, getRowInRows } from '../utils';
 import type { CalculatedColumn, Maybe } from '../types';
 
 interface ViewportColumnsArgs<R, SR> {
@@ -52,7 +52,7 @@ export function useViewportColumns<R, SR>({
 
       // check viewport rows
       for (let rowIdx = rowOverscanStartIdx; rowIdx <= rowOverscanEndIdx; rowIdx++) {
-        const row = rows[rowIdx];
+        const row = getRowInRows(rows, rowIdx);
         if (
           updateStartIdx(colIdx, getColSpan(column, lastFrozenColumnIndex, { type: 'ROW', row }))
         ) {
@@ -103,7 +103,7 @@ export function useViewportColumns<R, SR>({
   return useMemo((): readonly CalculatedColumn<R, SR>[] => {
     const viewportColumns: CalculatedColumn<R, SR>[] = [];
     for (let colIdx = 0; colIdx <= colOverscanEndIdx; colIdx++) {
-      const column = columns[colIdx];
+      const column = getColumnInColumns(columns, colIdx);
 
       if (colIdx < startIdx && !column.frozen) continue;
       viewportColumns.push(column);
diff --git a/src/hooks/useViewportRows.ts b/src/hooks/useViewportRows.ts
index 13b8502302..1eef73be7c 100644
--- a/src/hooks/useViewportRows.ts
+++ b/src/hooks/useViewportRows.ts
@@ -1,6 +1,6 @@
 import { useMemo } from 'react';
 
-import { floor, max, min } from '../utils';
+import { floor, getRowInRows, max, min } from '../utils';
 
 interface ViewportRowsArgs<R> {
   rows: readonly R[];
@@ -80,14 +80,14 @@ export function useViewportRows<R>({
     return {
       totalRowHeight,
       gridTemplateRows,
-      getRowTop: (rowIdx: number) => rowPositions[validateRowIdx(rowIdx)].top,
-      getRowHeight: (rowIdx: number) => rowPositions[validateRowIdx(rowIdx)].height,
+      getRowTop: (rowIdx: number) => getRowInRows(rowPositions, validateRowIdx(rowIdx)).top,
+      getRowHeight: (rowIdx: number) => getRowInRows(rowPositions, validateRowIdx(rowIdx)).height,
       findRowIdx(offset: number) {
         let start = 0;
         let end = rowPositions.length - 1;
         while (start <= end) {
           const middle = start + floor((end - start) / 2);
-          const currentOffset = rowPositions[middle].top;
+          const currentOffset = getRowInRows(rowPositions, middle).top;
 
           if (currentOffset === offset) return middle;
 
diff --git a/src/utils/colSpanUtils.ts b/src/utils/colSpanUtils.ts
index e986ba90b3..74e2eb2634 100644
--- a/src/utils/colSpanUtils.ts
+++ b/src/utils/colSpanUtils.ts
@@ -3,7 +3,7 @@ import type { CalculatedColumn, ColSpanArgs } from '../types';
 export function getColSpan<R, SR>(
   column: CalculatedColumn<R, SR>,
   lastFrozenColumnIndex: number,
-  args: ColSpanArgs<R, SR>
+  args: ColSpanArgs<NoInfer<R>, NoInfer<SR>>
 ): number | undefined {
   const colSpan = typeof column.colSpan === 'function' ? column.colSpan(args) : 1;
   if (
diff --git a/src/utils/index.ts b/src/utils/index.ts
index f6bd990888..3bc15351f0 100644
--- a/src/utils/index.ts
+++ b/src/utils/index.ts
@@ -10,6 +10,23 @@ export * from './styleUtils';
 
 export const { min, max, floor, sign, abs } = Math;
 
+export function getColumnInColumns<R, SR>(
+  columns: readonly CalculatedColumn<R, SR>[],
+  index: number
+) {
+  if (index < 0 || index >= columns.length) {
+    throw new Error(`columns[${index}] is out of bounds (length: ${columns.length})`);
+  }
+  return columns[index]!;
+}
+
+export function getRowInRows<R>(rows: readonly R[], index: number) {
+  if (index < 0 || index >= rows.length) {
+    throw new Error(`rows[${index}] is out of bounds (length: ${rows.length})`);
+  }
+  return rows[index]!;
+}
+
 export function assertIsValidKeyGetter<R, K extends React.Key>(
   keyGetter: Maybe<(row: NoInfer<R>) => K>
 ): asserts keyGetter is (row: R) => K {
diff --git a/src/utils/selectedCellUtils.ts b/src/utils/selectedCellUtils.ts
index db13f05da6..b14e23f111 100644
--- a/src/utils/selectedCellUtils.ts
+++ b/src/utils/selectedCellUtils.ts
@@ -5,6 +5,7 @@ import type {
   Maybe,
   Position
 } from '../types';
+import { getColumnInColumns, getRowInRows } from '.';
 import { getColSpan } from './colSpanUtils';
 
 interface IsSelectedCellEditableOpts<R, SR> {
@@ -18,8 +19,8 @@ export function isSelectedCellEditable<R, SR>({
   columns,
   rows
 }: IsSelectedCellEditableOpts<R, SR>): boolean {
-  const column = columns[selectedPosition.idx];
-  const row = rows[selectedPosition.rowIdx];
+  const column = getColumnInColumns(columns, selectedPosition.idx);
+  const row = getRowInRows(rows, selectedPosition.rowIdx);
   return isCellEditableUtil(column, row);
 }
 
@@ -76,19 +77,19 @@ function getSelectedCellColSpan<R, SR>({
   ) {
     return getColSpan(column, lastFrozenColumnIndex, {
       type: 'SUMMARY',
-      row: topSummaryRows[rowIdx + topSummaryRowsCount]
+      row: getRowInRows(topSummaryRows, rowIdx + topSummaryRowsCount)
     });
   }
 
   if (rowIdx >= 0 && rowIdx < rows.length) {
-    const row = rows[rowIdx];
+    const row = getRowInRows(rows, rowIdx);
     return getColSpan(column, lastFrozenColumnIndex, { type: 'ROW', row });
   }
 
   if (bottomSummaryRows) {
     return getColSpan(column, lastFrozenColumnIndex, {
       type: 'SUMMARY',
-      row: bottomSummaryRows[rowIdx - rows.length]
+      row: getRowInRows(bottomSummaryRows, rowIdx - rows.length)
     });
   }
 
@@ -145,7 +146,7 @@ export function getNextSelectedCellPosition<R, SR>({
   const setHeaderGroupColAndRowSpan = () => {
     if (moveNext) {
       // find the parent at the same row level
-      const nextColumn = columns[nextIdx];
+      const nextColumn = getColumnInColumns(columns, nextIdx);
       let { parent } = nextColumn;
       while (parent !== undefined) {
         const parentRowIdx = getParentRowIdx(parent);
@@ -157,7 +158,7 @@ export function getNextSelectedCellPosition<R, SR>({
       }
     } else if (moveUp) {
       // find the first reachable parent
-      const nextColumn = columns[nextIdx];
+      const nextColumn = getColumnInColumns(columns, nextIdx);
       let { parent } = nextColumn;
       let found = false;
       while (parent !== undefined) {
@@ -211,7 +212,7 @@ export function getNextSelectedCellPosition<R, SR>({
     // Find the last reachable parent for the new rowIdx
     // This check is needed when navigating to a column
     // that does not have a parent matching the new rowIdx
-    const nextColumn = columns[nextIdx];
+    const nextColumn = getColumnInColumns(columns, nextIdx);
     let { parent } = nextColumn;
     const nextParentRowIdx = nextRowIdx;
     nextRowIdx = mainHeaderRowIdx;
diff --git a/tsconfig.lib.json b/tsconfig.lib.json
index e1cc3af350..6e3366feca 100644
--- a/tsconfig.lib.json
+++ b/tsconfig.lib.json
@@ -4,7 +4,8 @@
     "composite": false,
     "declaration": true,
     "lib": ["ESNext", "DOM", "DOM.Iterable", "DOM.AsyncIterable"],
-    "noCheck": true
+    "noCheck": true,
+    "noUncheckedIndexedAccess": true
   },
   "files": ["src/index.ts"],
   "include": ["src/globals.d.ts"]
diff --git a/tsconfig.src.json b/tsconfig.src.json
index b535e9f135..91fda87a05 100644
--- a/tsconfig.src.json
+++ b/tsconfig.src.json
@@ -1,7 +1,8 @@
 {
   "extends": "./tsconfig.base.json",
   "compilerOptions": {
-    "lib": ["ESNext", "DOM", "DOM.Iterable", "DOM.AsyncIterable"]
+    "lib": ["ESNext", "DOM", "DOM.Iterable", "DOM.AsyncIterable"],
+    "noUncheckedIndexedAccess": true
   },
   "include": ["src/**/*"]
 }