diff --git a/examples/contour_tree_distributed/ContourTreeAppDataIO.h b/examples/contour_tree_distributed/ContourTreeAppDataIO.h
index acbf32b1c..2f3b5b7d0 100644
--- a/examples/contour_tree_distributed/ContourTreeAppDataIO.h
+++ b/examples/contour_tree_distributed/ContourTreeAppDataIO.h
@@ -233,6 +233,19 @@ bool read3DHDF5File(const int& mpi_rank,
   {
     count[2] = globalSize[2] - offset[2];
   }
+  // Check that we cover the end of the dataset
+  if (blockIndex[0] == blocksPerDim[0] - 1 && (vtkm::Id(offset[0] + count[0]) != globalSize[0]))
+  {
+    count[0] = globalSize[0] - offset[0];
+  }
+  if (blockIndex[1] == blocksPerDim[1] - 1 && (vtkm::Id(offset[1] + count[1]) != globalSize[1]))
+  {
+    count[1] = globalSize[1] - offset[1];
+  }
+  if (blockIndex[2] == blocksPerDim[2] - 1 && (vtkm::Id(offset[2] + count[2]) != globalSize[2]))
+  {
+    count[2] = globalSize[2] - offset[2];
+  }
   blockSize = vtkm::Id3{ static_cast<vtkm::Id>(count[0]),
                          static_cast<vtkm::Id>(count[1]),
                          static_cast<vtkm::Id>(count[2]) };