diff --git a/search_app.py b/search_app.py
index 730847d..da2d97e 100644
--- a/search_app.py
+++ b/search_app.py
@@ -384,6 +384,7 @@ def build_query_payload(
     use_fuzzy: bool = True,
     use_phrase: bool = True,
     use_query_string: bool = False,
+    include_external: bool = True,
 ) -> Dict:
     filters: List[Dict] = []
     should: List[Dict] = []
@@ -396,6 +397,9 @@ def build_query_payload(
     if year_filter:
         filters.append(year_filter)
 
+    if not include_external:
+        filters.append({"bool": {"must_not": [{"term": {"external_reference": True}}]}})
+
     if use_query_string:
         base_fields = ["title^3", "description^2", "transcript_full", "transcript_secondary_full"]
         qs_query = (query or "").strip() or "*"
@@ -916,6 +920,7 @@ def create_app(config: AppConfig = CONFIG) -> Flask:
         use_fuzzy = parse_flag("fuzzy", True)
         use_phrase = parse_flag("phrase", True)
         use_query_string = parse_flag("query_string", False)
+        include_external = parse_flag("external", True)
         if use_query_string:
             use_exact = use_fuzzy = use_phrase = False
 
@@ -928,6 +933,7 @@ def create_app(config: AppConfig = CONFIG) -> Flask:
             use_fuzzy=use_fuzzy,
             use_phrase=use_phrase,
             use_query_string=use_query_string,
+            include_external=include_external,
         )
         start = page * size
         if config.elastic.debug:
@@ -1005,6 +1011,7 @@ def create_app(config: AppConfig = CONFIG) -> Flask:
                     "referenced_by_count": source.get("referenced_by_count", 0),
                     "referenced_by": source.get("referenced_by", []),
                     "video_status": source.get("video_status"),
+                    "external_reference": source.get("external_reference"),
                 }
             )
 
@@ -1068,6 +1075,7 @@ def create_app(config: AppConfig = CONFIG) -> Flask:
         use_exact = parse_flag("exact", True)
         use_fuzzy = parse_flag("fuzzy", True)
         use_phrase = parse_flag("phrase", True)
+        include_external = parse_flag("external", True)
         if use_query_string:
             use_exact = use_fuzzy = use_phrase = False
 
@@ -1080,6 +1088,7 @@ def create_app(config: AppConfig = CONFIG) -> Flask:
             use_fuzzy=use_fuzzy,
             use_phrase=use_phrase,
             use_query_string=use_query_string,
+            include_external=include_external,
         )
         query = search_payload.get("query", {"match_all": {}})
 
diff --git a/static/app.js b/static/app.js
index 4da22d3..328b2a1 100644
--- a/static/app.js
+++ b/static/app.js
@@ -39,6 +39,7 @@
   const exactToggle = document.getElementById("exactToggle");
   const fuzzyToggle = document.getElementById("fuzzyToggle");
   const phraseToggle = document.getElementById("phraseToggle");
+  const externalToggle = document.getElementById("externalToggle");
   const queryToggle = document.getElementById("queryStringToggle");
   const searchBtn = document.getElementById("searchBtn");
   const aboutBtn = document.getElementById("aboutBtn");
@@ -139,6 +140,9 @@
     exactToggle.checked = parseBoolParam("exact", true);
     fuzzyToggle.checked = parseBoolParam("fuzzy", true);
     phraseToggle.checked = parseBoolParam("phrase", true);
+    if (externalToggle) {
+      externalToggle.checked = parseBoolParam("external", true);
+    }
     queryToggle.checked = parseBoolParam("query_string", false);
     applyQueryMode();
     rememberToggleState();
@@ -313,7 +317,7 @@
     }
   }
 
-  function updateUrl(q, sort, channels, year, page, size, exact, fuzzy, phrase, queryMode) {
+  function updateUrl(q, sort, channels, year, page, size, exact, fuzzy, phrase, queryMode, includeExternal) {
     const next = new URL(window.location.href);
     next.searchParams.set("q", q);
     next.searchParams.set("sort", sort);
@@ -331,6 +335,7 @@
     next.searchParams.set("fuzzy", fuzzy ? "1" : "0");
     next.searchParams.set("phrase", phrase ? "1" : "0");
     next.searchParams.set("query_string", queryMode ? "1" : "0");
+    next.searchParams.set("external", includeExternal ? "1" : "0");
     history.pushState({}, "", next.toString());
   }
 
@@ -1193,10 +1198,11 @@ async function updateFrequencyChart(term, channels, year, queryMode, toggles = {
   if (queryMode) {
     params.set("query_string", "1");
   }
-  const { exact = true, fuzzy = true, phrase = true } = toggles || {};
+  const { exact = true, fuzzy = true, phrase = true, external = true } = toggles || {};
   params.set("exact", exact ? "1" : "0");
   params.set("fuzzy", fuzzy ? "1" : "0");
   params.set("phrase", phrase ? "1" : "0");
+  params.set("external", external ? "1" : "0");
 
   clearFrequency("Loading timeline…");
   try {
@@ -1250,6 +1256,13 @@ async function updateFrequencyChart(term, channels, year, queryMode, toggles = {
       const headerMain = document.createElement("div");
       headerMain.className = "result-header-main";
       const badgeDefs = [];
+      if (item.external_reference) {
+        badgeDefs.push({
+          label: "External",
+          badgeType: "external",
+          title: "Indexed from an external reference source",
+        });
+      }
       if (item.highlightSource && item.highlightSource.primary) {
         badgeDefs.push({ label: "primary transcript", badgeType: "transcript-primary" });
       }
@@ -1516,6 +1529,7 @@ async function updateFrequencyChart(term, channels, year, queryMode, toggles = {
     let exact = !!exactToggle.checked;
     let fuzzy = !!fuzzyToggle.checked;
     let phrase = !!phraseToggle.checked;
+    const includeExternal = externalToggle ? externalToggle.checked : true;
     if (queryMode) {
       exact = false;
       fuzzy = false;
@@ -1531,7 +1545,19 @@ async function updateFrequencyChart(term, channels, year, queryMode, toggles = {
     currentPage = page;
 
     if (pushState) {
-      updateUrl(q, sort, channels, year, page, size, exact, fuzzy, phrase, queryMode);
+      updateUrl(
+        q,
+        sort,
+        channels,
+        year,
+        page,
+        size,
+        exact,
+        fuzzy,
+        phrase,
+        queryMode,
+        includeExternal
+      );
     }
 
     const params = new URLSearchParams();
@@ -1543,13 +1569,14 @@ async function updateFrequencyChart(term, channels, year, queryMode, toggles = {
     params.set("fuzzy", fuzzy ? "1" : "0");
     params.set("phrase", phrase ? "1" : "0");
     params.set("query_string", queryMode ? "1" : "0");
+    params.set("external", includeExternal ? "1" : "0");
     channels.forEach((id) => params.append("channel_id", id));
     if (year) params.set("year", year);
 
     const res = await fetch(`/api/search?${params.toString()}`);
     const payload = await res.json();
     renderResults(payload, page);
-    updateFrequencyChart(q, channels, year, queryMode, { exact, fuzzy, phrase });
+    updateFrequencyChart(q, channels, year, queryMode, { exact, fuzzy, phrase, external: includeExternal });
   }
 
   searchBtn.addEventListener("click", () => runSearch(0));
@@ -1580,6 +1607,9 @@ async function updateFrequencyChart(term, channels, year, queryMode, toggles = {
   exactToggle.addEventListener("change", () => { rememberToggleState(); runSearch(0); });
   fuzzyToggle.addEventListener("change", () => { rememberToggleState(); runSearch(0); });
   phraseToggle.addEventListener("change", () => { rememberToggleState(); runSearch(0); });
+  if (externalToggle) {
+    externalToggle.addEventListener("change", () => runSearch(0));
+  }
   if (queryToggle) {
     queryToggle.addEventListener("change", () => { applyQueryMode(); runSearch(0); });
   }
diff --git a/static/index.html b/static/index.html
index 217b382..f237563 100644
--- a/static/index.html
+++ b/static/index.html
@@ -81,6 +81,12 @@
               <span class="toggle-help">Boost exact phrases inside transcripts.</span>
             </div>
 
+            <div class="toggle-item">
+              <input type="checkbox" id="externalToggle" checked />
+              <label for="externalToggle">External</label>
+              <span class="toggle-help">Include externally referenced items.</span>
+            </div>
+
             <div class="toggle-item">
               <input type="checkbox" id="queryStringToggle" />
               <label for="queryStringToggle">Query string mode</label>
diff --git a/static/style.css b/static/style.css
index fc129d8..f76788f 100644
--- a/static/style.css
+++ b/static/style.css
@@ -571,6 +571,12 @@ body.modal-open {
   background: #8f4bff;
 }
 
+.badge--external {
+  background: #f5d08a;
+  color: #000;
+  border: 1px solid #cfa74f;
+}
+
 .badge-clickable {
   cursor: pointer;
 }