diff --git a/modules/core/locations.js b/modules/core/locations.js
index 39a7184e8..fe1fd4889 100644
--- a/modules/core/locations.js
+++ b/modules/core/locations.js
@@ -26,7 +26,9 @@ export function coreLocations() {
   let _loco = new LocationConflation();       // instance of a location-conflation resolver
   let _wp;                                    // instance of a which-polygon index
 
-  resolveLocationSet({ include: ['Q2'] });    // pre-resolve the worldwide locationSet
+  // pre-resolve the worldwide locationSet
+  const world = { locationSet: { include: ['Q2'] } };
+  resolveLocationSet(world);
   rebuildIndex();
 
   let _queue = [];
@@ -53,8 +55,14 @@ export function coreLocations() {
       .then(() => processQueue());
   }
 
-  function resolveLocationSet(locationSet) {
+  function resolveLocationSet(obj) {
+    if (obj.locationSetID) return;  // work was done already
+
     try {
+      const locationSet = obj.locationSet;
+      if (!locationSet) {
+        throw new Error('object missing locationSet property');
+      }
       const resolved = _loco.resolveLocationSet(locationSet);
       const locationSetID = resolved.id;
       if (!resolved.feature.geometry.coordinates.length || !resolved.feature.properties.area) {
@@ -66,7 +74,10 @@ export function coreLocations() {
         feature.properties.id = locationSetID;
         _resolvedFeatures[locationSetID] = feature;  // insert into cache
       }
-    } catch (err) { /* ignore? */ }
+    } catch (err) {
+      obj.locationSet = { include: ['Q2'] };  // default worldwide
+      obj.locationSetID = '+[Q2]';
+    }
   }
 
   function rebuildIndex() {
@@ -119,12 +130,28 @@ export function coreLocations() {
 
   //
   // `mergeLocationSets`
-  //  Accepts an Array of locationSets to merge into the index
+  //  Accepts an Array of Objects containing `locationSet` properties.
+  //  The locationSets will be resolved and indexed in the background.
+  //  [
+  //   { id: 'preset1', locationSet: {…} },
+  //   { id: 'preset2', locationSet: {…} },
+  //   { id: 'preset3', locationSet: {…} },
+  //   …
+  //  ]
+  //  After resolving and indexing, the Objects will be decorated with a
+  //  `locationSetID` property.
+  //  [
+  //   { id: 'preset1', locationSet: {…}, locationSetID: '+[Q2]' },
+  //   { id: 'preset2', locationSet: {…}, locationSetID: '+[Q30]' },
+  //   { id: 'preset3', locationSet: {…}, locationSetID: '+[Q2]' },
+  //   …
+  //  ]
+  //
   //  Returns a Promise fullfilled when the resolving/indexing has been completed
   //  This will take some seconds but happen in the background during browser idle time
   //
-  _this.mergeLocationSets = (locationSets) => {
-    if (!Array.isArray(locationSets)) return Promise.reject('nothing to do');
+  _this.mergeLocationSets = (objects) => {
+    if (!Array.isArray(objects)) return Promise.reject('nothing to do');
 
     // Resolve all locationSets -> geojson, processing data in chunks
     //
@@ -136,7 +163,7 @@ export function coreLocations() {
     // Some discussion and performance results on these tickets:
     // https://github.com/ideditor/location-conflation/issues/26
     // https://github.com/osmlab/name-suggestion-index/issues/4784#issuecomment-742003434
-    _queue = _queue.concat(utilArrayChunk(locationSets, 200));
+    _queue = _queue.concat(utilArrayChunk(objects, 200));
 
     // Everything after here will be deferred.
     if (!_inProcess) {
diff --git a/modules/presets/index.js b/modules/presets/index.js
index 04630598e..cbbf2d74d 100644
--- a/modules/presets/index.js
+++ b/modules/presets/index.js
@@ -88,8 +88,6 @@ export function presetIndex() {
   //   featureCollection: {}
   //}
   _this.merge = (d) => {
-    let newFields = [];
-    let newPresets = [];
     let newLocationSets = [];
 
     // Merge Fields
@@ -100,8 +98,7 @@ export function presetIndex() {
         if (f) {   // add or replace
           f = presetField(fieldID, f);
           if (f.locationSet) {
-            newFields.push(f);
-            newLocationSets.push(f.locationSet);
+            newLocationSets.push(f);
           } else {
             f.locationSet = { include: ['Q2'] };  // default worldwide
             f.locationSetID = '+[Q2]';
@@ -123,8 +120,7 @@ export function presetIndex() {
           const isAddable = !_addablePresetIDs || _addablePresetIDs.has(presetID);
           p = presetPreset(presetID, p, isAddable, _fields, _presets);
           if (p.locationSet) {
-            newPresets.push(p);
-            newLocationSets.push(p.locationSet);
+            newLocationSets.push(p);
           } else {
             p.locationSet = { include: ['Q2'] };  // default worldwide
             p.locationSetID = '+[Q2]';
@@ -195,13 +191,8 @@ export function presetIndex() {
     }
 
     // Resolve all locationSet features.
-    // When done, assign the locationSetIDs (we use these to quickly test where the preset/field is valid).
     if (newLocationSets.length) {
-      locationManager.mergeLocationSets(newLocationSets)
-        .then(() => {
-          newFields.forEach(f => f.locationSetID = locationManager.locationSetID(f.locationSet));
-          newPresets.forEach(p => p.locationSetID = locationManager.locationSetID(p.locationSet));
-        });
+      locationManager.mergeLocationSets(newLocationSets);
     }
 
     return _this;
diff --git a/modules/ui/success.js b/modules/ui/success.js
index b1cc29f51..5ef1af54c 100644
--- a/modules/ui/success.js
+++ b/modules/ui/success.js
@@ -34,15 +34,11 @@ export function uiSuccess(context) {
           locationManager.mergeCustomGeoJSON(vals[0]);
         }
 
-        const ociResources = Object.values(vals[1].resources);
-        const locationSets = ociResources.map(r => r.locationSet);
-
-        // Resolve all locationSet features.
-        // When done, assign the locationSetIDs (we use these to quickly test where each community is valid).
-        if (locationSets.length) {
-          return locationManager.mergeLocationSets(locationSets)
+        let ociResources = Object.values(vals[1].resources);
+        if (ociResources.length) {
+          // Resolve all locationSet features.
+          return locationManager.mergeLocationSets(ociResources)
             .then(() => {
-              ociResources.forEach(r => r.locationSetID = locationManager.locationSetID(r.locationSet));
               _oci = { resources: ociResources };
               return _oci;
             });