diff --git a/Gemfile b/Gemfile
index 74167afe..7ca8cb4d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -37,7 +37,7 @@ gem 'resource_api', git: 'https://github.com/performant-software/resource-api.gi
 gem 'jwt_auth', git: 'https://github.com/performant-software/jwt-auth.git', tag: 'v0.1.3'
 
 # Core data
-gem 'core_data_connector', git: 'https://github.com/performant-software/core-data-connector.git', tag: 'v0.1.121'
+gem 'core_data_connector', git: 'https://github.com/performant-software/core-data-connector.git', tag: 'v0.1.122'
 
 # IIIF
 gem 'triple_eye_effable', git: 'https://github.com/performant-software/triple-eye-effable.git', tag: 'v0.2.7'
diff --git a/Gemfile.lock b/Gemfile.lock
index 18ec28e8..374ae736 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 GIT
   remote: https://github.com/performant-software/core-data-connector.git
-  revision: c29a4f5d0ac39ecac405b08481dd21db171be081
-  tag: v0.1.121
+  revision: f10cb17b4bf53c0389c6d3d23e25eb6173c00759
+  tag: v0.1.122
   specs:
     core_data_connector (0.1.0)
       activerecord-postgis-adapter (~> 11.0)
diff --git a/client/package.json b/client/package.json
index 3320fba0..8ccc35a6 100644
--- a/client/package.json
+++ b/client/package.json
@@ -11,10 +11,10 @@
   "dependencies": {
     "@bunchtogether/vite-plugin-flow": "^1.0.2",
     "@clerk/react": "^6.0.1",
-    "@performant-software/geospatial": "^3.1.7",
-    "@performant-software/semantic-components": "^3.1.7",
-    "@performant-software/shared-components": "^3.1.7",
-    "@performant-software/user-defined-fields": "^3.1.7",
+    "@performant-software/geospatial": "^3.1.17",
+    "@performant-software/semantic-components": "^3.1.17",
+    "@performant-software/shared-components": "^3.1.17",
+    "@performant-software/user-defined-fields": "^3.1.17",
     "@peripleo/maplibre": "^0.8.7",
     "@peripleo/peripleo": "^0.8.7",
     "@samvera/clover-iiif": "^2.18.3",
diff --git a/client/src/components/MapCertaintyControl.js b/client/src/components/MapCertaintyControl.js
new file mode 100644
index 00000000..a24570d4
--- /dev/null
+++ b/client/src/components/MapCertaintyControl.js
@@ -0,0 +1,70 @@
+// @flow
+
+import cx from 'classnames';
+import React, { useCallback, useMemo, useState } from 'react';
+import { useTranslation } from 'react-i18next';
+import { TbCircleDashed } from 'react-icons/tb';
+import { MapControl } from '@performant-software/geospatial';
+import styles from './MapCertaintyControl.module.css';
+
+type Props = {
+  data: any,
+  onChange: (data: any) => void
+};
+
+const MapCertaintyControl = (props: Props) => {
+  const { t } = useTranslation();
+  const [showCertaintyRadiusInput, setShowCertaintyRadiusInput] = useState(false);
+
+  const certaintyRadius = useMemo(() => (
+    props.data?.certainty_radius || 0
+  ), [props.data]);
+
+  const onCertaintyRadiusChange = useCallback((e) => {
+    const radius = parseFloat(e.target.value) || 0;
+
+    props.onChange({
+      ...props.data,
+      certainty_radius: radius
+    });
+  }, [props.data, props.onChange]);
+
+  return (
+    <MapControl
+      position='bottom-left'
+    >
+      <div className={styles.certaintyRadiusControl}>
+        <button
+          className={cx(
+            'mapbox-gl-draw_ctrl-draw-btn',
+            'layer-button'
+          )}
+          onClick={() => setShowCertaintyRadiusInput(!showCertaintyRadiusInput)}
+          title={t('PlaceForm.labels.certaintyRadius')}
+          type='button'
+        >
+          <TbCircleDashed />
+        </button>
+        { showCertaintyRadiusInput && (
+          <div
+            className={cx(
+              styles.certaintyRadiusInputContainer,
+              'mapbox-gl-draw_ctrl-draw-btn'
+            )}
+          >
+            <input
+              className='ui input'
+              type='number'
+              value={certaintyRadius}
+              min={0}
+              step={0.01}
+              onChange={onCertaintyRadiusChange}
+            />
+          </div>
+        )}
+      </div>
+    </MapControl>
+  );
+};
+
+export default MapCertaintyControl;
diff --git a/client/src/components/MapCertaintyControl.module.css b/client/src/components/MapCertaintyControl.module.css
new file mode 100644
index 00000000..3dece1cb
--- /dev/null
+++ b/client/src/components/MapCertaintyControl.module.css
@@ -0,0 +1,21 @@
+.certaintyRadiusControl {
+  display: inline-flex;
+  justify-content: center;
+  align-items: center;
+  margin: 0;
+  padding: 0;
+}
+
+.certaintyRadiusControl .certaintyRadiusInputContainer {
+  margin: 0;
+  height: 20px;
+  position: absolute;
+  left: 40px;
+  top: -2px;
+  width: 100px;
+  background-color: white;
+}
+
+.certaintyRadiusControl > .ui.input {
+  margin: 0;
+}
diff --git a/client/src/components/PlaceForm.js b/client/src/components/PlaceForm.js
index 6bd4a96e..8098b571 100644
--- a/client/src/components/PlaceForm.js
+++ b/client/src/components/PlaceForm.js
@@ -1,6 +1,7 @@
 // @flow
 
 import {
+  CertaintyLayer,
   GeoJsonLayer,
   LayerMenu,
   MapControl,
@@ -29,6 +30,7 @@ import PlaceLayerModal from './PlaceLayerModal';
 import PlaceLayerUtils from '../utils/PlaceLayers';
 import PlaceNameModal from './PlaceNameModal';
 import styles from './PlaceForm.module.css';
+import MapCertaintyControl from './MapCertaintyControl';
 
 type Props = EditContainerProps & {
   item: PlaceType
@@ -62,7 +64,7 @@ const PlaceForm = (props: Props) => {
   }, [geocoding]);
 
   /**
-   * Memo-izes the names of the passed place layers.
+   * Memoizes the names of the passed place layers.
    */
   const layerNames = useMemo(() => _.pluck(props.item.place_layers, 'name'), [props.item.place_layers]);
 
@@ -115,7 +117,7 @@ const PlaceForm = (props: Props) => {
 
   /**
    * Sets map geometry data on the item, destroying any existing geometry record
-   * if all geometry is deleted. 
+   * if all geometry is deleted.
    */
   useEffect(() => {
     if (mapData !== null) {
@@ -124,7 +126,12 @@ const PlaceForm = (props: Props) => {
           place_geometry: { id: props.item.place_geometry.id, _destroy: true }
         });
       } else {
-        props.onSetState({ place_geometry: mapData })
+        props.onSetState({
+          place_geometry: {
+            geometry_json: mapData.geometry_json || props.item.place_geometry?.geometry_json,
+            properties: mapData.properties || props.item.place_geometry?.properties
+          }
+        });
       }
     }
   }, [mapData, props.item.place_geometry?.id]);
@@ -134,7 +141,20 @@ const PlaceForm = (props: Props) => {
    *
    * @type {function(*): *}
    */
-  const onMapChange = useCallback((data) => setMapData({ geometry_json: data }), []);
+  const onMapChange = (data) => setMapData({
+    properties: props.item.place_geometry?.properties,
+    geometry_json: data
+  });
+
+  /**
+   * Sets the new map properties on the state.
+   *
+   * @type {function(*): *}
+   */
+  const onPropertiesChange = (data) => setMapData({
+    geometry_json: props.item.place_geometry?.geometry_json,
+    properties: data
+  });
 
   /**
    * Sets the uploaded file as the GeoJSON object.
@@ -246,6 +266,10 @@ const PlaceForm = (props: Props) => {
           WebkitBoxShadow: 'rgba(0, 0, 0, 0.1) 0px 10px 15px -3px, rgba(0, 0, 0, 0.05) 0px 4px 6px -2px'
         }}
       >
+        <CertaintyLayer
+          geometry={{ geometry: props.item.place_geometry?.geometry_json }}
+          certaintyRadius={props.item.place_geometry?.properties?.certainty_radius || 0}
+        />
         <MapControl
           position='bottom-left'
         >
@@ -282,6 +306,10 @@ const PlaceForm = (props: Props) => {
             onSelection={onUpload}
           />
         </MapControl>
+        <MapCertaintyControl
+          data={props.item.place_geometry?.properties}
+          onChange={onPropertiesChange}
+        />
         <LayerMenu
           names={layerNames}
         >
diff --git a/client/src/i18n/en.json b/client/src/i18n/en.json
index 2a58f8ea..90cab96c 100644
--- a/client/src/i18n/en.json
+++ b/client/src/i18n/en.json
@@ -504,7 +504,8 @@
       "location": "Location",
       "names": "Names",
       "polygonMode": "Polygon mode",
-      "pointMode": "Point mode"
+      "pointMode": "Point mode",
+      "certaintyRadius": "Certainty radius (in KM)"
     },
     "placeLayers": {
       "columns": {
diff --git a/client/src/transforms/Place.js b/client/src/transforms/Place.js
index 29aca8ec..3ec39f0d 100644
--- a/client/src/transforms/Place.js
+++ b/client/src/transforms/Place.js
@@ -69,7 +69,7 @@ class Place extends BaseTransform {
   }
 
   /**
-   * Returns the place for POST/PUT requests as a plain Javascript object.
+   * Returns the place for POST/PUT requests as a plain JavaScript object.
    *
    * @param place
    *
diff --git a/client/src/transforms/PlaceGeometry.js b/client/src/transforms/PlaceGeometry.js
index 6c554428..0e1ebe61 100644
--- a/client/src/transforms/PlaceGeometry.js
+++ b/client/src/transforms/PlaceGeometry.js
@@ -34,7 +34,7 @@ class PlaceGeometry extends BaseTransform {
    *
    * @param place
    *
-   * @returns {{place_geometry: (*&{geometry_json: string})}}
+   * @returns {{place_geometry: (*&{geometry_json: string, properties: string})}}
    */
   toPayload(place: PlaceType) {
     const { place_geometry: placeGeometry } = place;
@@ -42,7 +42,8 @@ class PlaceGeometry extends BaseTransform {
     return {
       [this.getParameterName()]: {
         ..._.pick(placeGeometry, this.getPayloadKeys()),
-        geometry_json: JSON.stringify(placeGeometry?.geometry_json)
+        geometry_json: JSON.stringify(placeGeometry?.geometry_json),
+        properties: placeGeometry?.properties
       }
     };
   }
diff --git a/client/src/types/Place.js b/client/src/types/Place.js
index 474cc99d..72ece979 100644
--- a/client/src/types/Place.js
+++ b/client/src/types/Place.js
@@ -16,7 +16,8 @@ export type PlaceName = {
 
 export type PlaceGeometry = {
   id: number,
-  geometry_json: string
+  geometry_json: string,
+  properties: string
 };
 
 export type Place = {
diff --git a/client/yarn.lock b/client/yarn.lock
index 65bef1f2..e574ea0e 100644
--- a/client/yarn.lock
+++ b/client/yarn.lock
@@ -1846,10 +1846,10 @@
     remark-rehype "^11.1.0"
     unified "^11.0.4"
 
-"@performant-software/geospatial@^3.1.7":
-  version "3.1.7"
-  resolved "https://registry.yarnpkg.com/@performant-software/geospatial/-/geospatial-3.1.7.tgz#59a3db0f97888ecdba3e3fac4306712412f6c2e1"
-  integrity sha512-TZC7BJKetg8YFWdcCqCWe/ThCmSHEpISiT6b/QFCwjp/Lat2UBee/qpsfBybDesL24ainMfEit5ZsHS0fNh/4w==
+"@performant-software/geospatial@^3.1.17":
+  version "3.1.17"
+  resolved "https://registry.yarnpkg.com/@performant-software/geospatial/-/geospatial-3.1.17.tgz#7ef6dc4663a7e6b4333a5fa3d9a836ef00b360a6"
+  integrity sha512-kfb3DC5KV6AaE85whW1c15UXdRlacbLeyhhzxBsh64YHORORuIvKF4MKOTO9nQzcjwuuDDkWhuIg9oVWTsefEg==
   dependencies:
     "@allmaps/maplibre" "^1.0.0-beta.25"
     "@mapbox/mapbox-gl-draw" "1.4.3"
@@ -1861,10 +1861,10 @@
     react-map-gl "^8.0.4"
     underscore "^1.13.7"
 
-"@performant-software/semantic-components@^3.1.7":
-  version "3.1.7"
-  resolved "https://registry.yarnpkg.com/@performant-software/semantic-components/-/semantic-components-3.1.7.tgz#bc4a130ca9a95fe7f9abb2ec39b88d34d8e739fc"
-  integrity sha512-XQ0UyIoO77sZFjhVWp4V3V3VdtqTpZdN8mbL71HlsYA6ZXJfgBeFs58VLX9mEMGpKMnCATpw5FLqikWGrOkhQg==
+"@performant-software/semantic-components@^3.1.17":
+  version "3.1.17"
+  resolved "https://registry.yarnpkg.com/@performant-software/semantic-components/-/semantic-components-3.1.17.tgz#9aeede214994dc5dd802743671623251e2d92235"
+  integrity sha512-D8nCVALu91lM+YAu6zUpDHX9shhxJjUhkD/qmKPhaOgYhzsOGUzy72wuUYRcNu1Y1MTx14d1f09K/qeBAEcmaA==
   dependencies:
     "@react-google-maps/api" "^2.20.7"
     axios "^1.10.0"
@@ -1882,10 +1882,10 @@
     zotero-api-client "^0.40.0"
     zotero-translation-client "^5.0.1"
 
-"@performant-software/shared-components@^3.1.7":
-  version "3.1.7"
-  resolved "https://registry.yarnpkg.com/@performant-software/shared-components/-/shared-components-3.1.7.tgz#f4618db460003fa92349cc2d5aa9d93085f20be9"
-  integrity sha512-uLfIdG1kYGUwfa8B28EaI92bnBJz6ya2Idol+b1h/OY9Yu2z643aAMSEiERtAm4ufRnxzMkSeBOzJUWcUd3jnw==
+"@performant-software/shared-components@^3.1.17":
+  version "3.1.17"
+  resolved "https://registry.yarnpkg.com/@performant-software/shared-components/-/shared-components-3.1.17.tgz#f57880443a40b72f2ce415ac6a641b2bcfd8e108"
+  integrity sha512-LMXFiUHKmjX223aWqiui+wRzGuLPhPw6hS2YbPudfE+2Fx0jhoMfq0Ks4tMXmhgfdms7bNw8XAfyD+OG6CEGDg==
   dependencies:
     "@rails/activestorage" "^8.0.201"
     "@react-google-maps/api" "^2.20.7"
@@ -1901,10 +1901,10 @@
     underscore "^1.13.7"
     zotero-translation-client "^5.0.1"
 
-"@performant-software/user-defined-fields@^3.1.7":
-  version "3.1.7"
-  resolved "https://registry.yarnpkg.com/@performant-software/user-defined-fields/-/user-defined-fields-3.1.7.tgz#d6d5b2177f6ec3215db0668abcaa9e6801252a06"
-  integrity sha512-Wx6dIn0avVELoOhnsz6VpaE9w2p6AaeKi8mDxfM01AMoXXYrDMrwea+ch2LAUZ08t5UHfarvHDcyjMqvTW0T7g==
+"@performant-software/user-defined-fields@^3.1.17":
+  version "3.1.17"
+  resolved "https://registry.yarnpkg.com/@performant-software/user-defined-fields/-/user-defined-fields-3.1.17.tgz#95b5a58151f3f61a1f4ab5f018fd8b06f4b87e3c"
+  integrity sha512-3U4bWTIvvfAZvVce4ue3xIQrJOJ/nU4mFsAYxKltBll65ZTL6I1LZ3yadVE2UTGirUKPwjzIh7UbwM9u4nZdfw==
   dependencies:
     i18next "^25.3.2"
     semantic-ui-react "^2.1.5"
diff --git a/db/migrate/20260402204332_add_properties_to_place_geometries.core_data_connector.rb b/db/migrate/20260402204332_add_properties_to_place_geometries.core_data_connector.rb
new file mode 100644
index 00000000..8c2683a3
--- /dev/null
+++ b/db/migrate/20260402204332_add_properties_to_place_geometries.core_data_connector.rb
@@ -0,0 +1,6 @@
+# This migration comes from core_data_connector (originally 20260402204230)
+class AddPropertiesToPlaceGeometries < ActiveRecord::Migration[8.0]
+  def change
+    add_column :core_data_connector_place_geometries, :properties, :jsonb, default: {}
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index f6e78357..08cff001 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2026_03_10_203200) do
+ActiveRecord::Schema[8.0].define(version: 2026_04_02_204332) do
   create_schema "heroku_ext"
 
   # These are extensions that must be enabled in order to support this database
@@ -180,6 +180,7 @@
     t.geometry "geometry", limit: {srid: 0, type: "geometry"}
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.jsonb "properties", default: {}
     t.index ["place_id"], name: "index_core_data_connector_place_geometries_on_place_id"
   end