diff --git a/Source/IGListKit/IGListAdapter.m b/Source/IGListKit/IGListAdapter.m
index 1195708f..92c7a57a 100644
--- a/Source/IGListKit/IGListAdapter.m
+++ b/Source/IGListKit/IGListAdapter.m
@@ -901,10 +901,16 @@
 }
 
 - (NSArray<UICollectionViewCell *> *)fullyVisibleCellsForSectionController:(IGListSectionController *)sectionController {
+    const NSInteger section = [self sectionForSectionController:sectionController];
+    if (section == NSNotFound) {
+        // The section controller is not in the map, which can happen if the associated object was deleted or after a full reload.
+        return @[];
+    }
+
     NSMutableArray *cells = [NSMutableArray new];
     UICollectionView *collectionView = self.collectionView;
     NSArray *visibleCells = [collectionView visibleCells];
-    const NSInteger section = [self sectionForSectionController:sectionController];
+
     for (UICollectionViewCell *cell in visibleCells) {
         if ([collectionView indexPathForCell:cell].section == section) {
             const CGRect cellRect = [cell convertRect:cell.bounds toView:collectionView];
@@ -917,10 +923,16 @@
 }
 
 - (NSArray<UICollectionViewCell *> *)visibleCellsForSectionController:(IGListSectionController *)sectionController {
+    const NSInteger section = [self sectionForSectionController:sectionController];
+    if (section == NSNotFound) {
+        // The section controller is not in the map, which can happen if the associated object was deleted or after a full reload.
+        return @[];
+    }
+
     NSMutableArray *cells = [NSMutableArray new];
     UICollectionView *collectionView = self.collectionView;
     NSArray *visibleCells = [collectionView visibleCells];
-    const NSInteger section = [self sectionForSectionController:sectionController];
+
     for (UICollectionViewCell *cell in visibleCells) {
         if ([collectionView indexPathForCell:cell].section == section) {
             [cells addObject:cell];
@@ -930,10 +942,16 @@
 }
 
 - (NSArray<NSIndexPath *> *)visibleIndexPathsForSectionController:(IGListSectionController *) sectionController {
+    const NSInteger section = [self sectionForSectionController:sectionController];
+    if (section == NSNotFound) {
+        // The section controller is not in the map, which can happen if the associated object was deleted or after a full reload.
+        return @[];
+    }
+
     NSMutableArray *paths = [NSMutableArray new];
     UICollectionView *collectionView = self.collectionView;
     NSArray *visiblePaths = [collectionView indexPathsForVisibleItems];
-    const NSInteger section = [self sectionForSectionController:sectionController];
+
     for (NSIndexPath *path in visiblePaths) {
         if (path.section == section) {
             [paths addObject:path];
@@ -1105,8 +1123,16 @@
 }
 
 - (void)invalidateLayoutForSectionController:(IGListSectionController *)sectionController
-                                  completion:(void (^)(BOOL finished))completion{
+                                  completion:(void (^)(BOOL finished))completion {
     const NSInteger section = [self sectionForSectionController:sectionController];
+    if (section == NSNotFound) {
+        // The section controller is not in the map, which can happen if the associated object was deleted or after a full reload.
+        if (completion) {
+            completion(NO);
+        }
+        return;
+    }
+
     const NSInteger items = [_collectionView numberOfItemsInSection:section];
 
     NSMutableArray<NSIndexPath *> *indexPaths = [NSMutableArray new];
diff --git a/Tests/IGListAdapterTests.m b/Tests/IGListAdapterTests.m
index 86a985ce..c9b008a8 100644
--- a/Tests/IGListAdapterTests.m
+++ b/Tests/IGListAdapterTests.m
@@ -1843,4 +1843,57 @@
     [mockDelegate verify];
 }
 
+#pragma mark - Deleted Section Controllers
+
+- (void)test_whenSectionControllerRemoved_thatCellForIndexPathIsNil {
+    self.dataSource.objects = @[@1];
+    [self.adapter performUpdatesAnimated:NO completion:nil];
+    IGListSectionController *sectionController = [self.adapter sectionControllerForObject:@1];
+    self.dataSource.objects = @[@2];
+    [self.adapter performUpdatesAnimated:NO completion:nil];
+    XCTAssertNil([sectionController.collectionContext cellForItemAtIndex:0 sectionController:sectionController]);
+}
+
+- (void)test_whenSectionControllerRemoved_thatFullyVisibleCellsIsEmpty {
+    self.dataSource.objects = @[@1];
+    [self.adapter performUpdatesAnimated:NO completion:nil];
+    IGListSectionController *sectionController = [self.adapter sectionControllerForObject:@1];
+    self.dataSource.objects = @[@2];
+    [self.adapter performUpdatesAnimated:NO completion:nil];
+
+    NSArray<UICollectionViewCell *> *cells = [sectionController.collectionContext fullyVisibleCellsForSectionController:sectionController];
+    XCTAssertEqual(cells.count, 0);
+}
+
+- (void)test_whenSectionControllerRemoved_thatVisibleCellsIsEmpty {
+    self.dataSource.objects = @[@1];
+    [self.adapter performUpdatesAnimated:NO completion:nil];
+    IGListSectionController *sectionController = [self.adapter sectionControllerForObject:@1];
+    self.dataSource.objects = @[@2];
+    [self.adapter performUpdatesAnimated:NO completion:nil];
+
+    NSArray<UICollectionViewCell *> *cells = [sectionController.collectionContext visibleCellsForSectionController:sectionController];
+    XCTAssertEqual(cells.count, 0);
+}
+
+- (void)test_whenSectionControllerRemoved_thatVisibleIndexPathIsEmpty {
+    self.dataSource.objects = @[@1];
+    [self.adapter performUpdatesAnimated:NO completion:nil];
+    IGListSectionController *sectionController = [self.adapter sectionControllerForObject:@1];
+    self.dataSource.objects = @[@2];
+    [self.adapter performUpdatesAnimated:NO completion:nil];
+
+    NSArray<NSIndexPath *> *cells = [sectionController.collectionContext visibleIndexPathsForSectionController:sectionController];
+    XCTAssertEqual(cells.count, 0);
+}
+
+- (void)test_whenSectionControllerRemoved_thatDoesNotCrashOnInvalidatingLayout {
+    self.dataSource.objects = @[@1];
+    [self.adapter performUpdatesAnimated:NO completion:nil];
+    IGListSectionController *sectionController = [self.adapter sectionControllerForObject:@1];
+    self.dataSource.objects = @[@2];
+    [self.adapter performUpdatesAnimated:NO completion:nil];
+    [sectionController.collectionContext invalidateLayoutForSectionController:sectionController completion:nil];
+}
+
 @end