diff --git a/src/AppRouter.test.ts b/src/AppRouter.test.ts
index 2c9ab7a..ac1e614 100644
--- a/src/AppRouter.test.ts
+++ b/src/AppRouter.test.ts
@@ -199,17 +199,32 @@ describe("AppRouter", () => {
   });
 
   test("navigates to the tracked org sets page without a document reload", async () => {
-    vi.stubGlobal(
-      "fetch",
-      mockResolvedFetch({ ok: true, status: 200, json: async () => ({ orgSets: [] }) }),
-    );
+    const fetchMock = mockResolvedFetch({
+      ok: true,
+      status: 200,
+      json: async () => ({ orgSets: [] }),
+    });
+    vi.stubGlobal("fetch", fetchMock);
     const user = userEvent.setup();
 
     render(AppRouter);
-    await user.click(screen.getByRole("link", { name: "Tracked orgs" }));
+    await user.click(await screen.findByRole("link", { name: "Tracking 0 orgs" }));
 
     expect(window.location.pathname).toBe("/tracked");
     expect(await screen.findByRole("heading", { name: "Tracked org sets" })).toBeInTheDocument();
+    expect(await screen.findByRole("link", { name: "Tracking 0 orgs" })).toHaveAttribute(
+      "aria-current",
+      "page",
+    );
+    expect(
+      fetchMock.mock.calls.filter(([input]) => requestUrl(input) === "/api/reports/tracked"),
+    ).toHaveLength(2);
+    window.dispatchEvent(new Event("npm.report:tracked-orgs-changed"));
+    await waitFor(() =>
+      expect(
+        fetchMock.mock.calls.filter(([input]) => requestUrl(input) === "/api/reports/tracked"),
+      ).toHaveLength(3),
+    );
     expect(screen.getByRole("main")).toHaveFocus();
   });
 });
diff --git a/src/TrackedOrgSets.svelte b/src/TrackedOrgSets.svelte
index f03260a..51d3ec2 100644
--- a/src/TrackedOrgSets.svelte
+++ b/src/TrackedOrgSets.svelte
@@ -58,9 +58,7 @@
 </svelte:head>
 
 <div class="app">
-  <SiteHeader tracked>
-    <p class="tagline">Daily package trust across tracked npm org sets.</p>
-  </SiteHeader>
+  <SiteHeader tracked />
 
   <main tabindex="-1" aria-busy={loading}>
     <section class="tracked-page" aria-labelledby="tracked-title">
diff --git a/src/TrackedOrgSets.test.ts b/src/TrackedOrgSets.test.ts
index 7a8a68c..5c9ecff 100644
--- a/src/TrackedOrgSets.test.ts
+++ b/src/TrackedOrgSets.test.ts
@@ -34,6 +34,8 @@ describe("TrackedOrgSets", () => {
 
     render(TrackedOrgSets);
 
+    expect(screen.getByRole("link", { name: "Tracking … orgs" })).toBeInTheDocument();
+    expect(screen.getByRole("heading", { name: "Tracked org sets" })).toBeInTheDocument();
     expect(screen.getByRole("status")).toHaveTextContent("Loading tracked orgs…");
     expect(screen.getByRole("main")).toHaveAttribute("aria-busy", "true");
   });
@@ -47,6 +49,7 @@ describe("TrackedOrgSets", () => {
     const { container } = render(TrackedOrgSets);
 
     expect(await screen.findByText("1 set")).toBeInTheDocument();
+    expect(await screen.findByRole("link", { name: "Tracking 2 orgs" })).toBeInTheDocument();
     expect(screen.getByRole("main")).toHaveAttribute("aria-busy", "false");
     expect(screen.getByRole("link", { name: "acme, example" })).toHaveAttribute(
       "href",
diff --git a/src/components/DailyTrackingButton.svelte b/src/components/DailyTrackingButton.svelte
index 4653e27..9bb519d 100644
--- a/src/components/DailyTrackingButton.svelte
+++ b/src/components/DailyTrackingButton.svelte
@@ -46,6 +46,7 @@
       const body = data as ReportRerunScheduleStatus;
       scheduledFor = body.nextRunAt;
       status = "done";
+      window.dispatchEvent(new Event("npm.report:tracked-orgs-changed"));
       onToast("Daily tracking enabled");
     } catch (reason) {
       status = "error";
diff --git a/src/components/DailyTrackingButton.test.ts b/src/components/DailyTrackingButton.test.ts
index cb67811..cb54327 100644
--- a/src/components/DailyTrackingButton.test.ts
+++ b/src/components/DailyTrackingButton.test.ts
@@ -34,6 +34,8 @@ describe("DailyTrackingButton", () => {
 
   test("replaces the action with schedule status after enabling tracking", async () => {
     const user = userEvent.setup();
+    const trackingChanged = vi.fn<() => void>();
+    window.addEventListener("npm.report:tracked-orgs-changed", trackingChanged, { once: true });
     vi.stubGlobal(
       "fetch",
       mockResolvedFetch({
@@ -57,6 +59,7 @@ describe("DailyTrackingButton", () => {
         name: `Tracking daily, next run ${formatCompactDateTime("2026-06-28T12:00:00.000Z")}`,
       }),
     ).toBeInTheDocument();
+    expect(trackingChanged).toHaveBeenCalledOnce();
     expect(screen.queryByRole("button", { name: "Track daily" })).not.toBeInTheDocument();
   });
 
diff --git a/src/components/SiteHeader.svelte b/src/components/SiteHeader.svelte
index cda44fb..059a748 100644
--- a/src/components/SiteHeader.svelte
+++ b/src/components/SiteHeader.svelte
@@ -1,3 +1,28 @@
+<script module lang="ts">
+  import { parseOrNull, TrackedOrgSetsResponseSchema } from "#shared/schemas";
+
+  let trackedOrgCountRequest:
+    | { fetcher: typeof fetch; promise: Promise<number | null> }
+    | undefined;
+
+  function loadTrackedOrgCount(refresh = false): Promise<number | null> {
+    const fetcher = fetch;
+    if (refresh || trackedOrgCountRequest?.fetcher !== fetcher) {
+      trackedOrgCountRequest = {
+        fetcher,
+        promise: fetcher("/api/reports/tracked")
+          .then(async (response) => {
+            if (!response.ok) return null;
+            const body = parseOrNull(TrackedOrgSetsResponseSchema, await response.json());
+            return body ? new Set(body.orgSets.flatMap((orgSet) => orgSet.orgs)).size : null;
+          })
+          .catch(() => null),
+      };
+    }
+    return trackedOrgCountRequest.promise;
+  }
+</script>
+
 <script lang="ts">
   import type { Snippet } from "svelte";
   import ThemeToggle from "./ThemeToggle.svelte";
@@ -10,6 +35,36 @@
   }
 
   let { children, tracked = false }: Props = $props();
+  let trackedOrgCount = $state<number | null | undefined>(undefined);
+  let trackedOrgLabel = $derived(
+    trackedOrgCount === undefined
+      ? "Tracking … orgs"
+      : trackedOrgCount === null
+        ? "Tracking orgs"
+        : `Tracking ${trackedOrgCount} ${trackedOrgCount === 1 ? "org" : "orgs"}`,
+  );
+
+  $effect(() => {
+    let cancelled = false;
+
+    function updateCount(refresh = false): void {
+      loadTrackedOrgCount(refresh).then((count) => {
+        if (!cancelled) trackedOrgCount = count;
+      });
+    }
+
+    function handleTrackingChange(): void {
+      updateCount(true);
+    }
+
+    updateCount();
+    window.addEventListener("npm.report:tracked-orgs-changed", handleTrackingChange);
+
+    return () => {
+      cancelled = true;
+      window.removeEventListener("npm.report:tracked-orgs-changed", handleTrackingChange);
+    };
+  });
 </script>
 
 <header class="masthead">
@@ -19,12 +74,23 @@
         ><span>npm</span><img class="logo" src={logo} alt="" /><span>report</span></a
       >
     </h1>
-    <div class="masthead__controls">
-      <a class="masthead__tracked" href="/tracked" aria-current={tracked ? "page" : undefined}
-        >Tracked orgs</a
-      >
-      <ThemeToggle />
-      <TrustGlossary />
+    <div class="masthead__actions">
+      <nav class="masthead__nav" aria-label="Primary">
+        <a
+          class="masthead__nav-link"
+          href="/tracked"
+          aria-label={trackedOrgLabel}
+          aria-current={tracked ? "page" : undefined}
+          ><img class="masthead__nav-mark" src={logo} alt="" /><span>Tracking</span
+          >{#if trackedOrgCount !== null}<span class="masthead__nav-count"
+              >{trackedOrgCount ?? "…"}</span
+            >{/if}<span>{trackedOrgCount === 1 ? "org" : "orgs"}</span></a
+        >
+      </nav>
+      <div class="masthead__controls">
+        <ThemeToggle />
+        <TrustGlossary />
+      </div>
     </div>
   </div>
   {#if children}
diff --git a/src/styles.css b/src/styles.css
index c22eb55..dad186b 100644
--- a/src/styles.css
+++ b/src/styles.css
@@ -180,26 +180,59 @@ a:hover {
   gap: var(--space-lg);
   margin-bottom: var(--space-md);
 }
-.masthead__controls {
+.masthead__actions {
   display: flex;
   align-items: center;
-  gap: var(--space-sm);
+  margin-left: auto;
+  gap: var(--space-lg);
 }
-.masthead__tracked {
+.masthead__nav-link {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  gap: var(--space-xs);
+  min-width: 9.75rem;
   padding: var(--space-xs) var(--space-sm);
+  border: 1px solid var(--line);
+  border-radius: var(--radius);
+  background: var(--ink-850);
   color: var(--fg-dim);
   font-family: var(--mono);
   font-size: var(--text-xs);
   text-decoration: none;
   white-space: nowrap;
 }
-.masthead__tracked:hover,
-.masthead__tracked[aria-current="page"] {
+.masthead__nav-link:hover {
+  color: var(--fg);
+  border-color: var(--gold-dim);
+  background: var(--gold-soft);
+  text-decoration: none;
+}
+.masthead__nav-link[aria-current="page"] {
   color: var(--gold);
+  border-color: var(--gold-dim);
+  background: var(--gold-soft);
+}
+.masthead__nav-mark {
+  width: 1.5rem;
+  height: 1.5rem;
+  flex: none;
 }
-.masthead__tracked:focus-visible {
+.masthead__nav-count {
+  min-width: 2ch;
+  color: var(--gold);
+  font-variant-numeric: tabular-nums;
+  font-weight: 600;
+  text-align: center;
+}
+.masthead__nav-link:focus-visible {
   outline: 2px solid var(--gold-dim);
-  outline-offset: 2px;
+  outline-offset: 3px;
+}
+.masthead__controls {
+  display: flex;
+  align-items: center;
+  gap: var(--space-sm);
 }
 .glossary__btn {
   display: inline-flex;
@@ -512,7 +545,7 @@ a:hover {
     align-items: flex-start;
     flex-wrap: wrap;
   }
-  .masthead__controls {
+  .masthead__actions {
     margin-left: auto;
   }