diff --git a/docs/changelog/external-face-miss-pair.md b/docs/changelog/external-face-miss-pair.md
new file mode 100644
index 000000000..75b5bd8c0
--- /dev/null
+++ b/docs/changelog/external-face-miss-pair.md
@@ -0,0 +1,8 @@
+# Fixed error in checking paired faces in ExternalFaces filter
+
+The `ExternalFaces` filter uses hash codes to find duplicate (i.e.
+internal) faces. The issue with hash codes is that you have to deal with
+unique entries that have identical hashes. The worklet to count how many
+unique, unmatched faces were associated with each hash code was correct.
+However, the code to then grab the ith unique face in a hash was wrong.
+This has been fixed.
diff --git a/vtkm/filter/entity_extraction/worklet/ExternalFaces.h b/vtkm/filter/entity_extraction/worklet/ExternalFaces.h
index dbb891027..f89b2e2ea 100644
--- a/vtkm/filter/entity_extraction/worklet/ExternalFaces.h
+++ b/vtkm/filter/entity_extraction/worklet/ExternalFaces.h
@@ -452,8 +452,12 @@ private:
                                       cellSet.GetIndices(originCells[myIndex]),
                                       myFace);
       bool foundPair = false;
-      for (vtkm::IdComponent otherIndex = myIndex + 1; otherIndex < numCellsOnHash; otherIndex++)
+      for (vtkm::IdComponent otherIndex = 0; otherIndex < numCellsOnHash; otherIndex++)
       {
+        if (otherIndex == myIndex)
+        {
+          continue;
+        }
         vtkm::Id3 otherFace;
         vtkm::exec::CellFaceCanonicalId(originFaces[otherIndex],
                                         cellSet.GetCellShape(originCells[otherIndex]),