diff --git a/src/app/routes/AppRoutes.tsx b/src/app/routes/AppRoutes.tsx
new file mode 100644
index 0000000..4bc1825
--- /dev/null
+++ b/src/app/routes/AppRoutes.tsx
@@ -0,0 +1,15 @@
+import { Route, Routes } from 'react-router';
+import { AppPage } from '@/pages/app';
+import { MapPage } from '@/pages/map';
+import { NotFoundPage } from '@/pages/not-found';
+
+export function AppRoutes() {
+  return (
+    <Routes>
+      <Route path="/" element={<MapPage />} />
+      <Route path="/map" element={<MapPage />} />
+      <Route path="/app" element={<AppPage />} />
+      <Route path="*" element={<NotFoundPage />} />
+    </Routes>
+  );
+}
diff --git a/src/main.test.tsx b/src/main.test.tsx
new file mode 100644
index 0000000..6a90a12
--- /dev/null
+++ b/src/main.test.tsx
@@ -0,0 +1,17 @@
+import { render, screen } from '@testing-library/react';
+import { MemoryRouter } from 'react-router';
+import { describe, expect, it } from 'vitest';
+import { AppRoutes } from '@/app/routes/AppRoutes';
+
+describe('application routing', () => {
+  it('shows a not-found page for an unknown path', () => {
+    render(
+      <MemoryRouter initialEntries={['/missing-page']}>
+        <AppRoutes />
+      </MemoryRouter>,
+    );
+
+    expect(screen.getByRole('heading', { name: 'Страница не найдена' })).toBeVisible();
+    expect(screen.getByRole('link', { name: 'Вернуться к карте' })).toHaveAttribute('href', '/map');
+  });
+});
diff --git a/src/main.tsx b/src/main.tsx
index 6b510ed..e4cd43a 100644
--- a/src/main.tsx
+++ b/src/main.tsx
@@ -1,9 +1,8 @@
 import { StrictMode } from 'react';
 import { createRoot } from 'react-dom/client';
-import { BrowserRouter, Routes, Route } from 'react-router';
+import { BrowserRouter } from 'react-router';
 import { AppProviders } from '@/app/providers';
-import { AppPage } from '@/pages/app';
-import { MapPage } from '@/pages/map';
+import { AppRoutes } from '@/app/routes/AppRoutes';
 import '@/index.css';
 
 // VITE_API_MODE controls MSW registration.
@@ -25,11 +24,7 @@ function renderApp() {
     <StrictMode>
       <BrowserRouter>
         <AppProviders>
-          <Routes>
-            <Route path="/" element={<MapPage />} />
-            <Route path="/map" element={<MapPage />} />
-            <Route path="/app" element={<AppPage />} />
-          </Routes>
+          <AppRoutes />
         </AppProviders>
       </BrowserRouter>
     </StrictMode>,
diff --git a/src/pages/not-found/NotFoundPage.tsx b/src/pages/not-found/NotFoundPage.tsx
new file mode 100644
index 0000000..8950a72
--- /dev/null
+++ b/src/pages/not-found/NotFoundPage.tsx
@@ -0,0 +1,28 @@
+import { ArrowLeft, MapPinned } from 'lucide-react';
+import { Link } from 'react-router';
+
+export function NotFoundPage() {
+  return (
+    <main className="flex min-h-dvh items-center justify-center bg-zinc-50 px-4 py-10 sm:px-6">
+      <section aria-labelledby="not-found-page-title" className="w-full max-w-lg text-center">
+        <div className="mx-auto mb-6 flex size-16 items-center justify-center rounded-2xl bg-emerald-600 text-white shadow-lg shadow-emerald-600/20">
+          <MapPinned aria-hidden="true" className="size-8" />
+        </div>
+        <p className="text-sm font-semibold uppercase tracking-[0.2em] text-emerald-700">Ошибка 404</p>
+        <h1 id="not-found-page-title" className="mt-3 text-3xl font-bold tracking-tight text-zinc-900 sm:text-4xl">
+          Страница не найдена
+        </h1>
+        <p className="mx-auto mt-3 max-w-md text-base leading-6 text-zinc-600">
+          Возможно, ссылка устарела или адрес был введён с ошибкой.
+        </p>
+        <Link
+          className="mt-8 inline-flex items-center gap-2 rounded-xl bg-emerald-600 px-5 py-3 text-sm font-semibold text-white shadow-sm transition hover:bg-emerald-700 focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-emerald-600"
+          to="/map"
+        >
+          <ArrowLeft aria-hidden="true" className="size-4" />
+          Вернуться к карте
+        </Link>
+      </section>
+    </main>
+  );
+}
diff --git a/src/pages/not-found/index.ts b/src/pages/not-found/index.ts
new file mode 100644
index 0000000..642c600
--- /dev/null
+++ b/src/pages/not-found/index.ts
@@ -0,0 +1 @@
+export { NotFoundPage } from './NotFoundPage';
diff --git a/tests/e2e/not-found.spec.ts b/tests/e2e/not-found.spec.ts
new file mode 100644
index 0000000..5760e72
--- /dev/null
+++ b/tests/e2e/not-found.spec.ts
@@ -0,0 +1,8 @@
+import { expect, test } from '@playwright/test';
+
+test('unknown paths show the not-found page and a way back to the map', async ({ page }) => {
+  await page.goto('/missing-page');
+
+  await expect(page.getByRole('heading', { name: 'Страница не найдена' })).toBeVisible();
+  await expect(page.getByRole('link', { name: 'Вернуться к карте' })).toHaveAttribute('href', '/map');
+});