diff --git a/src/NotFoundPage.tsx b/src/NotFoundPage.tsx
new file mode 100644
index 000000000..be2754c69
--- /dev/null
+++ b/src/NotFoundPage.tsx
@@ -0,0 +1,10 @@
+import React from 'react'
+
+const NotFoundPage: React.FC = () => (
+  <div style={{ textAlign: 'center', marginTop: '50px' }}>
+    <h1>404 - Not Found</h1>
+    <p>The page you are looking for does not exist.</p>
+  </div>
+)
+
+export default NotFoundPage
diff --git a/src/router/aboutRoutes.tsx b/src/router/aboutRoutes.tsx
index 92d659b36..d0859656c 100644
--- a/src/router/aboutRoutes.tsx
+++ b/src/router/aboutRoutes.tsx
@@ -4,6 +4,7 @@ import About, { TabId, tabIds } from 'about/ui/about'
 import { CachedMarkupService } from 'markup/application/MarkupService'
 import { sitemapDefaults } from 'router/sitemap'
 import { HeadTagsService } from 'router/head'
+import NotFoundPage from 'NotFoundPage'
 import { newsletters } from 'about/ui/news'
 
 // ToDo:
@@ -44,6 +45,11 @@ export default function AboutRoutes({
       )}
       {...(sitemap && sitemapDefaults)}
     />,
+    <Route
+      key="AboutNotFound"
+      path="/about/*"
+      render={(): ReactNode => <NotFoundPage />}
+    />,
     <Redirect
       from="/about"
       to="/about/fragmentarium"
diff --git a/src/router/bibliographyRoutes.tsx b/src/router/bibliographyRoutes.tsx
index 4525a5adc..f1213e1e1 100644
--- a/src/router/bibliographyRoutes.tsx
+++ b/src/router/bibliographyRoutes.tsx
@@ -7,6 +7,7 @@ import { BibliographySlugs, sitemapDefaults } from 'router/sitemap'
 import { HeadTagsService } from 'router/head'
 import AfoRegisterService from 'afo-register/application/AfoRegisterService'
 import FragmentService from 'fragmentarium/application/FragmentService'
+import NotFoundPage from 'NotFoundPage'
 
 export default function BibliographyRoutes({
   sitemap,
@@ -25,6 +26,7 @@ export default function BibliographyRoutes({
     <Route
       key="BibliographyEditorNew"
       path="/bibliography/references/new-reference"
+      exact
       render={(props): ReactNode => (
         <BibliographyEditor
           bibliographyService={bibliographyService}
@@ -36,6 +38,7 @@ export default function BibliographyRoutes({
     <Route
       key="BibliographyViewerAndEditor"
       path="/bibliography/references/:id"
+      exact
       render={(props): ReactNode => (
         <HeadTagsService
           title="Bibliography entry: eBL"
@@ -55,6 +58,7 @@ export default function BibliographyRoutes({
     <Route
       key="Bibliography references search"
       path="/bibliography/references"
+      exact
       render={(props): ReactNode => (
         <HeadTagsService
           title="Bibliography References: eBL"
@@ -74,6 +78,7 @@ export default function BibliographyRoutes({
     <Route
       key="Bibliography AfO-Register search"
       path="/bibliography/afo-register"
+      exact
       render={(props): ReactNode => (
         <HeadTagsService
           title="Bibliography AfO-Register: eBL"
@@ -90,6 +95,11 @@ export default function BibliographyRoutes({
       )}
       {...(sitemap && sitemapDefaults)}
     />,
+    <Route
+      key="BibliographyNotFound"
+      path="/bibliography/*"
+      render={(): ReactNode => <NotFoundPage />}
+    />,
     <Redirect
       from="/bibliography"
       to="/bibliography/afo-register"
diff --git a/src/router/corpusRoutes.tsx b/src/router/corpusRoutes.tsx
index df34e9363..33bf91df4 100644
--- a/src/router/corpusRoutes.tsx
+++ b/src/router/corpusRoutes.tsx
@@ -15,7 +15,7 @@ import Corpus, { genres } from 'corpus/ui/Corpus'
 import { sitemapDefaults, ChapterSlugs, TextSlugs } from 'router/sitemap'
 import MarkupService from 'markup/application/MarkupService'
 import { HeadTagsService } from 'router/head'
-
+import NotFoundPage from 'NotFoundPage'
 function parseChapterId(params): ChapterId {
   return {
     textId: parseTextId(params),
@@ -149,5 +149,10 @@ export default function CorpusRoutes({
         }),
       })}
     />,
+    <Route
+      key="CorpusNotFound"
+      path="/corpus/*"
+      render={(): ReactNode => <NotFoundPage />}
+    />,
   ]
 }
diff --git a/src/router/dictionaryRoutes.tsx b/src/router/dictionaryRoutes.tsx
index b4995d33e..71ab629a2 100644
--- a/src/router/dictionaryRoutes.tsx
+++ b/src/router/dictionaryRoutes.tsx
@@ -9,6 +9,7 @@ import { Route } from 'react-router-dom'
 import SignService from 'signs/application/SignService'
 import { DictionarySlugs, sitemapDefaults } from 'router/sitemap'
 import { HeadTagsService } from 'router/head'
+import NotFoundPage from 'NotFoundPage'
 
 export default function DictionaryRoutes({
   sitemap,
@@ -29,6 +30,7 @@ export default function DictionaryRoutes({
     <Route
       key="WordEditor"
       path="/dictionary/:id/edit"
+      exact
       render={({ match }): ReactNode => (
         <WordEditor
           wordService={wordService}
@@ -39,6 +41,7 @@ export default function DictionaryRoutes({
     <Route
       key="WordDisplay"
       path="/dictionary/:id"
+      exact
       render={({ match }): ReactNode => (
         <HeadTagsService
           title="Dictionary entry: eBL"
@@ -61,6 +64,7 @@ export default function DictionaryRoutes({
     <Route
       key="Dictionary"
       path="/dictionary"
+      exact
       render={(props): ReactNode => (
         <HeadTagsService
           title="Search dictionary: eBL"
@@ -71,5 +75,10 @@ export default function DictionaryRoutes({
       )}
       {...(sitemap && sitemapDefaults)}
     />,
+    <Route
+      key="DictionaryNotFound"
+      path="/dictionary/*"
+      render={(): ReactNode => <NotFoundPage />}
+    />,
   ]
 }
diff --git a/src/router/fragmentariumRoutes.tsx b/src/router/fragmentariumRoutes.tsx
index 5ee436e67..9d65f8d97 100644
--- a/src/router/fragmentariumRoutes.tsx
+++ b/src/router/fragmentariumRoutes.tsx
@@ -22,7 +22,7 @@ import { HeadTagsService } from 'router/head'
 import BibliographyService from 'bibliography/application/BibliographyService'
 import { FindspotService } from 'fragmentarium/application/FindspotService'
 import AfoRegisterService from 'afo-register/application/AfoRegisterService'
-
+import NotFoundPage from 'NotFoundPage'
 function parseStringParam(location: Location, param: string): string | null {
   const value = parse(location.search)[param]
   return _.isArray(value) ? value.join('') : value
@@ -78,6 +78,7 @@ export default function FragmentariumRoutes({
     <Route
       key="FragmentariumSearch"
       path="/fragmentarium/search"
+      exact
       render={({ location }): ReactNode => (
         <HeadTagsService
           title="Fragmentarium search: eBL"
@@ -99,6 +100,7 @@ export default function FragmentariumRoutes({
     <Route
       key="FragmentLineToVecRanking"
       path="/fragmentarium/:id/match"
+      exact
       render={({ match }): ReactNode => (
         <HeadTagsService
           title="Fragmentarium line to vector ranking: eBL"
@@ -118,6 +120,7 @@ export default function FragmentariumRoutes({
     <Route
       key="TagSignsView"
       path="/fragmentarium/:id/annotate"
+      exact
       render={({ match }): ReactNode => (
         <TagSignsView
           signService={signService}
@@ -129,6 +132,7 @@ export default function FragmentariumRoutes({
     <Route
       key="FragmentView"
       path="/fragmentarium/:id"
+      exact
       render={({ match, location }): ReactNode => (
         <SessionContext.Consumer>
           {(session) => (
@@ -157,6 +161,7 @@ export default function FragmentariumRoutes({
     <Route
       key="Fragmentarium"
       path="/fragmentarium"
+      exact
       render={(): ReactNode => (
         <HeadTagsService
           title="Fragmentarium: eBL"
@@ -176,5 +181,10 @@ export default function FragmentariumRoutes({
       )}
       {...(sitemap && sitemapDefaults)}
     />,
+    <Route
+      key="FragmentariumNotFound"
+      path="/Fragmentarium/*"
+      render={(): ReactNode => <NotFoundPage />}
+    />,
   ]
 }
diff --git a/src/router/notFoundRoutes.test.tsx b/src/router/notFoundRoutes.test.tsx
new file mode 100644
index 000000000..aa7019f18
--- /dev/null
+++ b/src/router/notFoundRoutes.test.tsx
@@ -0,0 +1,177 @@
+import React from 'react'
+import { render, screen } from '@testing-library/react'
+import { Router, Switch } from 'react-router-dom'
+import { getServices } from 'test-support/AppDriver'
+import { createMemoryHistory } from 'history'
+import AboutRoutes from './aboutRoutes'
+import FragmentariumRoutes from './fragmentariumRoutes'
+import BibliographyRoutes from './bibliographyRoutes'
+import CorpusRoutes from './corpusRoutes'
+import DictionaryRoutes from './dictionaryRoutes'
+import SignRoutes from './signRoutes'
+import ToolsRoutes from './toolsRoutes'
+
+describe('NotFoundPage rendering in FragmentariumRoutes', () => {
+  const nonExistentRoutes = [
+    '/fragmentarium/search/non-existent',
+    '/fragmentarium/Fragment.12345/match/non-existent',
+    '/fragmentarium/Fragment.12345/annotate/non-existent',
+    '/fragmentarium/Fragment.12345/non-existent',
+  ]
+  nonExistentRoutes.forEach((path) => {
+    const history = createMemoryHistory({ initialEntries: [path] })
+    test(`renders NotFoundPage for "${path}"`, () => {
+      render(
+        <Router history={history}>
+          <Switch>
+            {[...FragmentariumRoutes({ ...getServices(), sitemap: false })]}
+          </Switch>
+        </Router>
+      )
+      expect(
+        screen.getByText(/The page you are looking for does not exist./i)
+      ).toBeInTheDocument()
+    })
+  })
+})
+
+describe('NotFoundPage rendering in AboutRoutes', () => {
+  const nonExistentAboutRoutes = [
+    '/about/non-existent-page',
+    '/about/invalid-section',
+    '/about/undefined-route',
+  ]
+  nonExistentAboutRoutes.forEach((path) => {
+    const history = createMemoryHistory({ initialEntries: [path] })
+    test(`renders NotFoundPage for "${path}"`, () => {
+      render(
+        <Router history={history}>
+          <Switch>
+            {[...AboutRoutes({ ...getServices(), sitemap: false })]}
+          </Switch>
+        </Router>
+      )
+      expect(
+        screen.getByText(/The page you are looking for does not exist./i)
+      ).toBeInTheDocument()
+    })
+  })
+})
+
+describe('NotFoundPage rendering in BibliographyRoutes', () => {
+  const nonExistentAboutRoutes = [
+    '/bibliography/search/non-existent',
+    '/bibliography/afo-register/non-existent-page',
+    '/bibliography/afo-register/invalid-section',
+    '/bibliography/afo-register/undefined-route',
+  ]
+  nonExistentAboutRoutes.forEach((path) => {
+    const history = createMemoryHistory({ initialEntries: [path] })
+    test(`renders NotFoundPage for "${path}"`, () => {
+      render(
+        <Router history={history}>
+          <Switch>
+            {[...BibliographyRoutes({ ...getServices(), sitemap: false })]}
+          </Switch>
+        </Router>
+      )
+      expect(
+        screen.getByText(/The page you are looking for does not exist./i)
+      ).toBeInTheDocument()
+    })
+  })
+})
+
+describe('NotFoundPage rendering in CorpusRoutes', () => {
+  const nonExistentAboutRoutes = [
+    '/corpus/Corpus.12345/non-existent-page',
+    '/corpus/Corpus.12345/invalid-section',
+    '/corpus/Corpus.12345/undefined-route',
+  ]
+  nonExistentAboutRoutes.forEach((path) => {
+    const history = createMemoryHistory({ initialEntries: [path] })
+    test(`renders NotFoundPage for "${path}"`, () => {
+      render(
+        <Router history={history}>
+          <Switch>
+            {[...CorpusRoutes({ ...getServices(), sitemap: false })]}
+          </Switch>
+        </Router>
+      )
+      expect(
+        screen.getByText(/The page you are looking for does not exist./i)
+      ).toBeInTheDocument()
+    })
+  })
+})
+
+describe('NotFoundPage rendering in DictionaryRoutes', () => {
+  const nonExistentAboutRoutes = [
+    '/dictionary/search/non-existent',
+    '/dictionary/Dictionary.12345/non-existent-page',
+    '/dictionary/Dictionary.12345/invalid-section',
+    '/dictionary/Dictionary.12345/undefined-route',
+  ]
+  nonExistentAboutRoutes.forEach((path) => {
+    const history = createMemoryHistory({ initialEntries: [path] })
+    test(`renders NotFoundPage for "${path}"`, () => {
+      render(
+        <Router history={history}>
+          <Switch>
+            {[...DictionaryRoutes({ ...getServices(), sitemap: false })]}
+          </Switch>
+        </Router>
+      )
+      expect(
+        screen.getByText(/The page you are looking for does not exist./i)
+      ).toBeInTheDocument()
+    })
+  })
+})
+
+describe('NotFoundPage rendering in SignRoutes', () => {
+  const nonExistentAboutRoutes = [
+    '/signs/search/non-existent',
+    '/signs/Signs.12345/non-existent-page',
+    '/signs/Signs.12345/invalid-section',
+    '/signs/Signs.12345/undefined-route',
+  ]
+  nonExistentAboutRoutes.forEach((path) => {
+    const history = createMemoryHistory({ initialEntries: [path] })
+    test(`renders NotFoundPage for "${path}"`, () => {
+      render(
+        <Router history={history}>
+          <Switch>
+            {[...SignRoutes({ ...getServices(), sitemap: false })]}
+          </Switch>
+        </Router>
+      )
+      expect(
+        screen.getByText(/The page you are looking for does not exist./i)
+      ).toBeInTheDocument()
+    })
+  })
+})
+
+describe('NotFoundPage rendering in ToolsRoutes', () => {
+  const nonExistentAboutRoutes = [
+    '/tools/date-converter/non-existent-page',
+    '/tools/date-converter/invalid-section',
+    '/tools/date-converter/undefined-route',
+  ]
+  nonExistentAboutRoutes.forEach((path) => {
+    const history = createMemoryHistory({ initialEntries: [path] })
+    test(`renders NotFoundPage for "${path}"`, () => {
+      render(
+        <Router history={history}>
+          <Switch>
+            {[...ToolsRoutes({ ...getServices(), sitemap: false })]}
+          </Switch>
+        </Router>
+      )
+      expect(
+        screen.getByText(/The page you are looking for does not exist./i)
+      ).toBeInTheDocument()
+    })
+  })
+})
diff --git a/src/router/router.tsx b/src/router/router.tsx
index 2577bcb17..cbcb5b1fe 100644
--- a/src/router/router.tsx
+++ b/src/router/router.tsx
@@ -24,6 +24,7 @@ import ToolsRoutes from 'router/toolsRoutes'
 
 import Sitemap, { sitemapDefaults, Slugs } from 'router/sitemap'
 import Header from 'Header'
+import NotFoundPage from 'NotFoundPage'
 import { helmetContext } from 'router/head'
 import { HelmetProvider } from 'react-helmet-async'
 import { FindspotService } from 'fragmentarium/application/FindspotService'
@@ -51,6 +52,7 @@ export default function Router(services: Services): JSX.Element {
         </Route>
         <Route exact path="/sitemap/sitemap.xml" />
         {WebsiteRoutes(services, false)}
+        <Route component={NotFoundPage} />
       </Switch>
     </HelmetProvider>
   )
diff --git a/src/router/signRoutes.tsx b/src/router/signRoutes.tsx
index 99f2125f1..8ef01723d 100644
--- a/src/router/signRoutes.tsx
+++ b/src/router/signRoutes.tsx
@@ -6,6 +6,7 @@ import SignDisplay from 'signs/ui/display/SignDisplay'
 import Signs from 'signs/ui/search/Signs'
 import { SignSlugs, sitemapDefaults } from 'router/sitemap'
 import { HeadTagsService } from 'router/head'
+import NotFoundPage from 'NotFoundPage'
 
 export default function SignRoutes({
   sitemap,
@@ -22,6 +23,7 @@ export default function SignRoutes({
     <Route
       key="signDisplay"
       path="/signs/:id"
+      exact
       render={({ match }): ReactNode => (
         <HeadTagsService
           title="Cuneiform sign display: eBL"
@@ -42,6 +44,7 @@ export default function SignRoutes({
     <Route
       key="signs"
       path="/signs"
+      exact
       render={(props): ReactNode => (
         <HeadTagsService
           title="Cuneiform sign search: eBL"
@@ -52,5 +55,10 @@ export default function SignRoutes({
       )}
       {...(sitemap && sitemapDefaults)}
     />,
+    <Route
+      key="SignsNotFound"
+      path="/signs/*"
+      render={(): ReactNode => <NotFoundPage />}
+    />,
   ]
 }
diff --git a/src/router/toolsRoutes.tsx b/src/router/toolsRoutes.tsx
index 34f2b3900..9896cd978 100644
--- a/src/router/toolsRoutes.tsx
+++ b/src/router/toolsRoutes.tsx
@@ -17,6 +17,7 @@ import DateConverterForm, {
 import ListOfKings from 'chronology/ui/Kings/BrinkmanKingsTable'
 import _ from 'lodash'
 import 'about/ui/about.sass'
+import NotFoundPage from 'NotFoundPage'
 
 const tabIds = ['date-converter', 'list-of-kings'] as const
 type TabId = typeof tabIds[number]
@@ -71,8 +72,8 @@ export default function ToolsRoutes({
   return [
     <Route
       key="tools-tabs"
-      exact
       path={`/tools/:id(${tabIds.join('|')})`}
+      exact
       render={(props: RouteComponentProps<{ id: string }>): ReactNode => (
         <HeadTagsService
           title="Tools: eBL"
@@ -86,6 +87,12 @@ export default function ToolsRoutes({
       )}
       {...(sitemap && sitemapDefaults)}
     />,
+    <Route
+      key="ToolsNotFound"
+      path="/tools/*"
+      exact
+      render={(): ReactNode => <NotFoundPage />}
+    />,
     <Redirect
       from="/tools"
       to="/tools/date-converter"
diff --git a/src/test-support/AppDriver.tsx b/src/test-support/AppDriver.tsx
index 30d04625a..dc04e688c 100644
--- a/src/test-support/AppDriver.tsx
+++ b/src/test-support/AppDriver.tsx
@@ -34,8 +34,22 @@ import AfoRegisterRepository from 'afo-register/infrastructure/AfoRegisterReposi
 import AfoRegisterService from 'afo-register/application/AfoRegisterService'
 import { FindspotService } from 'fragmentarium/application/FindspotService'
 import { ApiFindspotRepository } from 'fragmentarium/infrastructure/FindspotRepository'
-
-function createApp(api): JSX.Element {
+import FakeApi from 'test-support/FakeApi'
+
+export function getServices(
+  api: any = FakeApi
+): {
+  signService: SignService
+  wordService: WordService
+  fragmentService: FragmentService
+  fragmentSearchService: FragmentSearchService
+  bibliographyService: BibliographyService
+  textService: TextService
+  markupService: MarkupService
+  cachedMarkupService: CachedMarkupService
+  afoRegisterService: AfoRegisterService
+  findspotService: FindspotService
+} {
   const wordRepository = new WordRepository(api)
   const fragmentRepository = new FragmentRepository(api)
   const imageRepository = new ApiImageRepository(api)
@@ -64,20 +78,22 @@ function createApp(api): JSX.Element {
   const cachedMarkupService = new CachedMarkupService(api, bibliographyService)
   const afoRegisterService = new AfoRegisterService(afoRegisterRepository)
   const findspotService = new FindspotService(findspotRepository)
-  return (
-    <App
-      signService={signService}
-      wordService={wordService}
-      fragmentService={fragmentService}
-      fragmentSearchService={fragmentSearchService}
-      bibliographyService={bibliographyService}
-      textService={textService}
-      markupService={markupService}
-      cachedMarkupService={cachedMarkupService}
-      afoRegisterService={afoRegisterService}
-      findspotService={findspotService}
-    />
-  )
+  return {
+    signService,
+    wordService,
+    fragmentService,
+    fragmentSearchService,
+    bibliographyService,
+    textService,
+    markupService,
+    cachedMarkupService,
+    afoRegisterService,
+    findspotService,
+  }
+}
+
+function createApp(api): JSX.Element {
+  return <App {...getServices(api)} />
 }
 
 const breadcrumbs = {