diff --git a/package-lock.json b/package-lock.json
index 8affa03a43..b8d82da0f5 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,8 +9,10 @@
       "version": "0.0.1",
       "dependencies": {
         "@maptiler/geocoding-control": "^1.2.2",
+        "@turf/area": "^6.5.0",
         "govuk-frontend": "^5.2.0",
         "govuk-svelte": "github:acteng/govuk-svelte",
+        "maplibre-draw-polygon": "github:dabreegster/maplibre-draw-polygon",
         "svelte-maplibre": "^0.8.2",
         "uuid": "^9.0.1"
       },
@@ -19,6 +21,7 @@
         "@sveltejs/kit": "^2.0.0",
         "@sveltejs/vite-plugin-svelte": "^3.0.0",
         "@types/eslint": "^8.56.5",
+        "@types/geojson": "^7946.0.14",
         "@types/uuid": "^9.0.8",
         "@typescript-eslint/eslint-plugin": "^7.2.0",
         "@typescript-eslint/parser": "^7.2.0",
@@ -948,6 +951,141 @@
         "vite": "^5.0.0"
       }
     },
+    "node_modules/@turf/area": {
+      "version": "6.5.0",
+      "resolved": "https://registry.npmjs.org/@turf/area/-/area-6.5.0.tgz",
+      "integrity": "sha512-xCZdiuojokLbQ+29qR6qoMD89hv+JAgWjLrwSEWL+3JV8IXKeNFl6XkEJz9HGkVpnXvQKJoRz4/liT+8ZZ5Jyg==",
+      "dependencies": {
+        "@turf/helpers": "^6.5.0",
+        "@turf/meta": "^6.5.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/turf"
+      }
+    },
+    "node_modules/@turf/bbox": {
+      "version": "6.5.0",
+      "resolved": "https://registry.npmjs.org/@turf/bbox/-/bbox-6.5.0.tgz",
+      "integrity": "sha512-RBbLaao5hXTYyyg577iuMtDB8ehxMlUqHEJiMs8jT1GHkFhr6sYre3lmLsPeYEi/ZKj5TP5tt7fkzNdJ4GIVyw==",
+      "dependencies": {
+        "@turf/helpers": "^6.5.0",
+        "@turf/meta": "^6.5.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/turf"
+      }
+    },
+    "node_modules/@turf/bearing": {
+      "version": "6.5.0",
+      "resolved": "https://registry.npmjs.org/@turf/bearing/-/bearing-6.5.0.tgz",
+      "integrity": "sha512-dxINYhIEMzgDOztyMZc20I7ssYVNEpSv04VbMo5YPQsqa80KO3TFvbuCahMsCAW5z8Tncc8dwBlEFrmRjJG33A==",
+      "dependencies": {
+        "@turf/helpers": "^6.5.0",
+        "@turf/invariant": "^6.5.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/turf"
+      }
+    },
+    "node_modules/@turf/destination": {
+      "version": "6.5.0",
+      "resolved": "https://registry.npmjs.org/@turf/destination/-/destination-6.5.0.tgz",
+      "integrity": "sha512-4cnWQlNC8d1tItOz9B4pmJdWpXqS0vEvv65bI/Pj/genJnsL7evI0/Xw42RvEGROS481MPiU80xzvwxEvhQiMQ==",
+      "dependencies": {
+        "@turf/helpers": "^6.5.0",
+        "@turf/invariant": "^6.5.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/turf"
+      }
+    },
+    "node_modules/@turf/distance": {
+      "version": "6.5.0",
+      "resolved": "https://registry.npmjs.org/@turf/distance/-/distance-6.5.0.tgz",
+      "integrity": "sha512-xzykSLfoURec5qvQJcfifw/1mJa+5UwByZZ5TZ8iaqjGYN0vomhV9aiSLeYdUGtYRESZ+DYC/OzY+4RclZYgMg==",
+      "dependencies": {
+        "@turf/helpers": "^6.5.0",
+        "@turf/invariant": "^6.5.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/turf"
+      }
+    },
+    "node_modules/@turf/helpers": {
+      "version": "6.5.0",
+      "resolved": "https://registry.npmjs.org/@turf/helpers/-/helpers-6.5.0.tgz",
+      "integrity": "sha512-VbI1dV5bLFzohYYdgqwikdMVpe7pJ9X3E+dlr425wa2/sMJqYDhTO++ec38/pcPvPE6oD9WEEeU3Xu3gza+VPw==",
+      "funding": {
+        "url": "https://opencollective.com/turf"
+      }
+    },
+    "node_modules/@turf/invariant": {
+      "version": "6.5.0",
+      "resolved": "https://registry.npmjs.org/@turf/invariant/-/invariant-6.5.0.tgz",
+      "integrity": "sha512-Wv8PRNCtPD31UVbdJE/KVAWKe7l6US+lJItRR/HOEW3eh+U/JwRCSUl/KZ7bmjM/C+zLNoreM2TU6OoLACs4eg==",
+      "dependencies": {
+        "@turf/helpers": "^6.5.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/turf"
+      }
+    },
+    "node_modules/@turf/line-intersect": {
+      "version": "6.5.0",
+      "resolved": "https://registry.npmjs.org/@turf/line-intersect/-/line-intersect-6.5.0.tgz",
+      "integrity": "sha512-CS6R1tZvVQD390G9Ea4pmpM6mJGPWoL82jD46y0q1KSor9s6HupMIo1kY4Ny+AEYQl9jd21V3Scz20eldpbTVA==",
+      "dependencies": {
+        "@turf/helpers": "^6.5.0",
+        "@turf/invariant": "^6.5.0",
+        "@turf/line-segment": "^6.5.0",
+        "@turf/meta": "^6.5.0",
+        "geojson-rbush": "3.x"
+      },
+      "funding": {
+        "url": "https://opencollective.com/turf"
+      }
+    },
+    "node_modules/@turf/line-segment": {
+      "version": "6.5.0",
+      "resolved": "https://registry.npmjs.org/@turf/line-segment/-/line-segment-6.5.0.tgz",
+      "integrity": "sha512-jI625Ho4jSuJESNq66Mmi290ZJ5pPZiQZruPVpmHkUw257Pew0alMmb6YrqYNnLUuiVVONxAAKXUVeeUGtycfw==",
+      "dependencies": {
+        "@turf/helpers": "^6.5.0",
+        "@turf/invariant": "^6.5.0",
+        "@turf/meta": "^6.5.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/turf"
+      }
+    },
+    "node_modules/@turf/meta": {
+      "version": "6.5.0",
+      "resolved": "https://registry.npmjs.org/@turf/meta/-/meta-6.5.0.tgz",
+      "integrity": "sha512-RrArvtsV0vdsCBegoBtOalgdSOfkBrTJ07VkpiCnq/491W67hnMWmDu7e6Ztw0C3WldRYTXkg3SumfdzZxLBHA==",
+      "dependencies": {
+        "@turf/helpers": "^6.5.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/turf"
+      }
+    },
+    "node_modules/@turf/nearest-point-on-line": {
+      "version": "6.5.0",
+      "resolved": "https://registry.npmjs.org/@turf/nearest-point-on-line/-/nearest-point-on-line-6.5.0.tgz",
+      "integrity": "sha512-WthrvddddvmymnC+Vf7BrkHGbDOUu6Z3/6bFYUGv1kxw8tiZ6n83/VG6kHz4poHOfS0RaNflzXSkmCi64fLBlg==",
+      "dependencies": {
+        "@turf/bearing": "^6.5.0",
+        "@turf/destination": "^6.5.0",
+        "@turf/distance": "^6.5.0",
+        "@turf/helpers": "^6.5.0",
+        "@turf/invariant": "^6.5.0",
+        "@turf/line-intersect": "^6.5.0",
+        "@turf/meta": "^6.5.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/turf"
+      }
+    },
     "node_modules/@types/cookie": {
       "version": "0.6.0",
       "resolved": "https://registry.npmjs.org/@types/cookie/-/cookie-0.6.0.tgz",
@@ -2125,6 +2263,23 @@
       "resolved": "https://registry.npmjs.org/geo-coordinates-parser/-/geo-coordinates-parser-1.6.6.tgz",
       "integrity": "sha512-+zmVBzbTrC/LyFUMcYrvUqi+XUYkJ6bWqPHywfCsMYLa9BEGHEzLsBgltwXS9Ul5oJcFbrdt2y/CjjxNtTTQ+w=="
     },
+    "node_modules/geojson-rbush": {
+      "version": "3.2.0",
+      "resolved": "https://registry.npmjs.org/geojson-rbush/-/geojson-rbush-3.2.0.tgz",
+      "integrity": "sha512-oVltQTXolxvsz1sZnutlSuLDEcQAKYC/uXt9zDzJJ6bu0W+baTI8LZBaTup5afzibEH4N3jlq2p+a152wlBJ7w==",
+      "dependencies": {
+        "@turf/bbox": "*",
+        "@turf/helpers": "6.x",
+        "@turf/meta": "6.x",
+        "@types/geojson": "7946.0.8",
+        "rbush": "^3.0.1"
+      }
+    },
+    "node_modules/geojson-rbush/node_modules/@types/geojson": {
+      "version": "7946.0.8",
+      "resolved": "https://registry.npmjs.org/@types/geojson/-/geojson-7946.0.8.tgz",
+      "integrity": "sha512-1rkryxURpr6aWP7R786/UQOkJ3PcpQiWkAXBmdWc7ryFWqN6a4xfK7BtjXvFBKO9LjQ+MWQSWxYeZX1OApnArA=="
+    },
     "node_modules/geojson-vt": {
       "version": "3.2.1",
       "resolved": "https://registry.npmjs.org/geojson-vt/-/geojson-vt-3.2.1.tgz",
@@ -2639,6 +2794,17 @@
         "node": ">=12"
       }
     },
+    "node_modules/maplibre-draw-polygon": {
+      "version": "0.0.1",
+      "resolved": "git+ssh://git@github.com/dabreegster/maplibre-draw-polygon.git#ee9f2f1efd3c911fc90cbcfa7ceab87f23609cea",
+      "dependencies": {
+        "@turf/nearest-point-on-line": "^6.5.0",
+        "svelte-maplibre": "^0.8.2"
+      },
+      "peerDependencies": {
+        "svelte": "^4.0.0"
+      }
+    },
     "node_modules/maplibre-gl": {
       "version": "4.1.0",
       "resolved": "https://registry.npmjs.org/maplibre-gl/-/maplibre-gl-4.1.0.tgz",
@@ -3152,6 +3318,14 @@
       "resolved": "https://registry.npmjs.org/quickselect/-/quickselect-2.0.0.tgz",
       "integrity": "sha512-RKJ22hX8mHe3Y6wH/N3wCM6BWtjaxIyyUIkpHOvfFnxdI4yD4tBXEBKSbriGujF6jnSVkJrffuo6vxACiSSxIw=="
     },
+    "node_modules/rbush": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/rbush/-/rbush-3.0.1.tgz",
+      "integrity": "sha512-XRaVO0YecOpEuIvbhbpTrZgoiI6xBlz6hnlr6EHhd+0x9ase6EmeN+hdwwUaJvLcsFFQ8iWVF1GAK1yB0BWi0w==",
+      "dependencies": {
+        "quickselect": "^2.0.0"
+      }
+    },
     "node_modules/readdirp": {
       "version": "3.6.0",
       "resolved": "https://registry.npmjs.org/readdirp/-/readdirp-3.6.0.tgz",
diff --git a/package.json b/package.json
index a563ea9f8a..87825f51f9 100644
--- a/package.json
+++ b/package.json
@@ -16,6 +16,7 @@
     "@sveltejs/kit": "^2.0.0",
     "@sveltejs/vite-plugin-svelte": "^3.0.0",
     "@types/eslint": "^8.56.5",
+    "@types/geojson": "^7946.0.14",
     "@types/uuid": "^9.0.8",
     "@typescript-eslint/eslint-plugin": "^7.2.0",
     "@typescript-eslint/parser": "^7.2.0",
@@ -34,8 +35,10 @@
   "type": "module",
   "dependencies": {
     "@maptiler/geocoding-control": "^1.2.2",
+    "@turf/area": "^6.5.0",
     "govuk-frontend": "^5.2.0",
     "govuk-svelte": "github:acteng/govuk-svelte",
+    "maplibre-draw-polygon": "github:dabreegster/maplibre-draw-polygon",
     "svelte-maplibre": "^0.8.2",
     "uuid": "^9.0.1"
   }
diff --git a/src/routes/area_check/data.ts b/src/routes/area_check/data.ts
index 65d2d5b1a2..6593523276 100644
--- a/src/routes/area_check/data.ts
+++ b/src/routes/area_check/data.ts
@@ -1,4 +1,5 @@
 import { writable } from "svelte/store";
+import type { Feature, Polygon } from "geojson";
 
 export interface State {
   summary: {
@@ -17,6 +18,7 @@ export interface State {
     // TODO number
     schemeAreaSizeKm2: string;
     notes: string;
+    polygon: Feature<Polygon> | null;
   };
   // Exactly 13 entries, matching up with the scorecard questions. The values are the stringified scores.
   existingScores: string[];
@@ -57,6 +59,7 @@ export function emptyState(): State {
       inspectorEmail: "",
       schemeAreaSizeKm2: "",
       notes: "",
+      polygon: null,
     },
     existingScores: Array(13).fill(""),
     proposedScores: Array(13).fill(""),
diff --git a/src/routes/area_check/summary/+page.svelte b/src/routes/area_check/summary/+page.svelte
index 1bb4b9ea5c..cf9c08ca52 100644
--- a/src/routes/area_check/summary/+page.svelte
+++ b/src/routes/area_check/summary/+page.svelte
@@ -84,5 +84,10 @@
 
   <TextArea label="Notes" bind:value={$state.summary.notes} />
 
+  <h2>Network context</h2>
+  <p>
+    Please add a drawing of the area being assessed below, including the
+    location of measures proposed by the scheme.
+  </p>
   <DrawArea />
 </div>
diff --git a/src/routes/area_check/summary/DrawArea.svelte b/src/routes/area_check/summary/DrawArea.svelte
index 661ccf1a82..5c48b50750 100644
--- a/src/routes/area_check/summary/DrawArea.svelte
+++ b/src/routes/area_check/summary/DrawArea.svelte
@@ -1,8 +1,84 @@
 <script lang="ts">
-  import { MapLibre } from "svelte-maplibre";
+  import { state } from "../data";
+  import area from "@turf/area";
+  import { onDestroy } from "svelte";
+  import { WarningButton, DefaultButton, SecondaryButton } from "govuk-svelte";
+  import {
+    undoLength,
+    PolygonTool,
+    PolygonToolLayer,
+  } from "maplibre-draw-polygon";
+  import { MapLibre, GeoJSON, FillLayer, type Map } from "svelte-maplibre";
   import { Geocoder } from "$lib";
+
+  // TODO Is it worth trying to preserve the map while navigating to other pages?
+  let map: Map | null = null;
+
+  $: gj = $state.summary.polygon ?? {
+    type: "FeatureCollection" as const,
+    features: [],
+  };
+
+  let draw: PolygonTool | null = null;
+
+  // TODO HMR is not working correctly
+  onDestroy(() => {
+    draw?.tearDown();
+  });
+
+  // Auto-start the tool
+  $: if (map) {
+    start();
+  }
+
+  function start() {
+    if (!map) {
+      return;
+    }
+    draw = new PolygonTool(map);
+    if ($state.summary.polygon) {
+      draw.editExisting($state.summary.polygon);
+    } else {
+      draw.startNew();
+    }
+    draw.addEventListenerSuccess(async (f) => {
+      draw = null;
+      $state.summary.polygon = f;
+    });
+    draw.addEventListenerFailure(() => {
+      draw = null;
+      // Leave previous polygon alone
+    });
+  }
+
+  function reset() {
+    $state.summary.polygon = null;
+    start();
+  }
 </script>
 
+{#if draw}
+  <div style="display: flex; justify-content: space-between;">
+    <SecondaryButton on:click={() => draw?.finish()}>Finish</SecondaryButton>
+    <SecondaryButton on:click={() => draw?.cancel()}>Cancel</SecondaryButton>
+    <SecondaryButton disabled={$undoLength == 0} on:click={() => draw?.undo()}>
+      {#if $undoLength == 0}
+        Undo
+      {:else}
+        Undo ({$undoLength})
+      {/if}
+    </SecondaryButton>
+  </div>
+{:else if map}
+  <DefaultButton on:click={start}>Edit polygon</DefaultButton>
+  {#if $state.summary.polygon}
+    <WarningButton on:click={reset}>Delete and start over</WarningButton>
+    <p>Polygon area: {area($state.summary.polygon).toFixed(1)} square meters</p>
+  {/if}
+{:else}
+  <p>Map loading...</p>
+{/if}
+
 <div style="position: relative; width: 100%; height: 300px;">
   <MapLibre
     style={`https://api.maptiler.com/maps/uk-openzoomstack-light/style.json?key=${import.meta.env.VITE_MAPTILER_API_KEY}`}
@@ -12,7 +88,20 @@
       console.log(e.detail.error);
     }}
     let:map
+    bind:map
   >
     <Geocoder {map} />
+    <PolygonToolLayer />
+    <GeoJSON data={gj}>
+      <FillLayer
+        layout={{
+          visibility: draw ? "none" : "visible",
+        }}
+        paint={{
+          "fill-color": "red",
+          "fill-opacity": 0.8,
+        }}
+      />
+    </GeoJSON>
   </MapLibre>
 </div>