diff --git a/data/fields/historic.json b/data/fields/historic.json
index bc04d388..b36758cf 100644
--- a/data/fields/historic.json
+++ b/data/fields/historic.json
@@ -17,6 +17,7 @@
             "manor": "Manor House",
             "memorial": "Memorial",
             "milestone": "Milestone",
+            "millstone": "Millstone",
             "mine": "Mine",
             "mine_shaft": "Mine Shaft",
             "monument": "Monument",
diff --git a/interim/source_strings.yaml b/interim/source_strings.yaml
index 09fa0921..e5900f76 100644
--- a/interim/source_strings.yaml
+++ b/interim/source_strings.yaml
@@ -2679,6 +2679,8 @@ en:
           memorial: Memorial
           # historic=milestone
           milestone: Milestone
+          # historic=millstone
+          millstone: Millstone
           # historic=mine
           mine: Mine
           # historic=mine_shaft