diff --git a/js/id/id.js b/js/id/id.js
index 273a6b846..0283b6ab2 100644
--- a/js/id/id.js
+++ b/js/id/id.js
@@ -58,9 +58,15 @@ window.iD = function () {
         return context;
     };
 
-    context.locale = function(_, path) {
-        locale = _;
+    context.locale = function(loc, path) {
+        locale = loc;
         localePath = path;
+
+        // Also set iD.detect().locale (unless we detected 'en-us' and openstreetmap wants 'en')..
+        if (!(loc.toLowerCase() === 'en' && iD.detect().locale.toLowerCase() === 'en-us')) {
+            iD.detect().locale = loc;
+        }
+
         return context;
     };
 
diff --git a/js/id/ui/scale.js b/js/id/ui/scale.js
index d24d00fb9..f49f2ee36 100644
--- a/js/id/ui/scale.js
+++ b/js/id/ui/scale.js
@@ -1,11 +1,11 @@
 iD.ui.Scale = function(context) {
     var projection = context.projection,
-        imperial = (iD.detect().locale.toLowerCase() === 'en-us'),
         maxLength = 180,
         tickHeight = 8;
 
     function scaleDefs(loc1, loc2) {
         var lat = (loc2[1] + loc1[1]) / 2,
+            imperial = (iD.detect().locale.toLowerCase() === 'en-us'),
             conversion = (imperial ? 3.28084 : 1),
             dist = iD.geo.lonToMeters(loc2[0] - loc1[0], lat) * conversion,
             scale = { dist: 0, px: 0, text: '' },