diff --git a/src/server.js b/src/server.js
index c770999..6a5ce2d 100644
--- a/src/server.js
+++ b/src/server.js
@@ -103,7 +103,11 @@ async function route(req, res) {
       clearLoginFailures(req);
       return sendJsonWithHeaders(res, 200, loginHeaders(config), { ok: true });
     }
-    if (url.pathname === '/login' || url.pathname === '/login.html' || url.pathname === '/styles.css' || url.pathname === '/login.js') return serveStatic(req, res);
+    if (url.pathname === '/login' || url.pathname === '/login.html') {
+      if (isAuthenticated(req, config)) return redirect(res, '/');
+      return serveStatic(req, res);
+    }
+    if (url.pathname === '/styles.css' || url.pathname === '/login.js') return serveStatic(req, res);
     if (!isAuthenticated(req, config)) {
       if (url.pathname.startsWith('/api/')) return sendJson(res, 401, { ok: false, error: 'Authentication required.' });
       return redirect(res, '/login');
diff --git a/src/services/auth.js b/src/services/auth.js
index 69bea6b..1b60064 100644
--- a/src/services/auth.js
+++ b/src/services/auth.js
@@ -3,6 +3,7 @@ import { existsSync, mkdirSync, readFileSync, writeFileSync, chmodSync } from 'n
 import { dirname } from 'node:path';
 
 const COOKIE_NAME = 'kanban_session';
+const SESSION_MAX_AGE_SECONDS = 365 * 24 * 60 * 60;
 const attempts = new Map();
 const LOGIN_WINDOW_MS = 5 * 60 * 1000;
 const MAX_LOGIN_FAILURES = 8;
@@ -101,7 +102,7 @@ export function isAuthenticated(req, config) {
 export function loginHeaders(config) {
   const secure = config.authSecureCookie ? ' Secure;' : '';
   return {
-    'set-cookie': `${COOKIE_NAME}=${encodeURIComponent(config.auth.token)}; HttpOnly; SameSite=Strict; Path=/; Max-Age=2592000;${secure}`
+    'set-cookie': `${COOKIE_NAME}=${encodeURIComponent(config.auth.token)}; HttpOnly; SameSite=Strict; Path=/; Max-Age=${SESSION_MAX_AGE_SECONDS};${secure}`
   };
 }
 
diff --git a/test/auth.test.js b/test/auth.test.js
new file mode 100644
index 0000000..ca55699
--- /dev/null
+++ b/test/auth.test.js
@@ -0,0 +1,67 @@
+import { mkdtempSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import test from 'node:test';
+import assert from 'node:assert/strict';
+
+test('login persists authentication and skips the login page on later visits', async () => {
+  const testDirectory = mkdtempSync(join(tmpdir(), 'local-kanban-auth-'));
+  const token = 'test-only-auth-token';
+  process.env.KANBAN_CONFIG = join(testDirectory, 'config.json');
+  process.env.KANBAN_STATE = join(testDirectory, 'state.json');
+  process.env.KANBAN_AUTH_TOKEN = token;
+  process.env.KANBAN_AUTH_SECURE_COOKIE = '1';
+  process.env.KANBAN_REQUIRE_HTTPS = '0';
+
+  const { createKanbanServer } = await import(`../src/server.js?auth-test=${Date.now()}`);
+  const server = createKanbanServer();
+
+  try {
+    await new Promise((resolve) => server.listen(0, '127.0.0.1', resolve));
+    const { port } = server.address();
+    const origin = `http://127.0.0.1:${port}`;
+
+    const initialLoginPage = await fetch(`${origin}/login`, { redirect: 'manual' });
+    assert.equal(initialLoginPage.status, 200);
+
+    const rejectedLogin = await fetch(`${origin}/api/auth/login`, {
+      method: 'POST',
+      headers: { 'content-type': 'application/json' },
+      body: JSON.stringify({ token: 'wrong-token' })
+    });
+    assert.equal(rejectedLogin.status, 401);
+    assert.equal(rejectedLogin.headers.get('set-cookie'), null);
+
+    const loginResponse = await fetch(`${origin}/api/auth/login`, {
+      method: 'POST',
+      headers: { 'content-type': 'application/json' },
+      body: JSON.stringify({ token })
+    });
+    assert.equal(loginResponse.status, 200);
+
+    const setCookie = loginResponse.headers.get('set-cookie');
+    assert.match(setCookie, /^kanban_session=[^;]+;/);
+    const cookie = setCookie.split(';', 1)[0];
+
+    const laterLoginPage = await fetch(`${origin}/login`, {
+      headers: { cookie },
+      redirect: 'manual'
+    });
+    assert.equal(laterLoginPage.status, 302);
+    assert.equal(laterLoginPage.headers.get('location'), '/');
+    assert.match(setCookie, /Max-Age=31536000/);
+    assert.match(setCookie, /HttpOnly/);
+    assert.match(setCookie, /Secure/);
+
+    const logoutResponse = await fetch(`${origin}/api/auth/logout`, {
+      method: 'POST',
+      headers: { cookie }
+    });
+    assert.equal(logoutResponse.status, 200);
+    assert.match(logoutResponse.headers.get('set-cookie'), /^kanban_session=;/);
+    assert.match(logoutResponse.headers.get('set-cookie'), /Max-Age=0/);
+  } finally {
+    await new Promise((resolve) => server.close(resolve));
+    rmSync(testDirectory, { recursive: true, force: true });
+  }
+});