diff --git a/_config.yml b/_config.yml
index b063788..624928c 100644
--- a/_config.yml
+++ b/_config.yml
@@ -29,6 +29,7 @@ sitemap:
     exclude:
         # Even if you can see the existence of these pages here, I don't
         # wish to get search engine attention to them.
+        - "/404.html"
         - "/bot.html"
         - "/channel.html"
 include: [PGP, PHP, keybase.txt, robots.txt]
diff --git a/robots.txt b/robots.txt
index 642ca82..66e46d2 100644
--- a/robots.txt
+++ b/robots.txt
@@ -3,6 +3,7 @@ Allow: /
 
 # I prefer search engines to not advertise these pages even if you can find
 # them here or in `_config.yml`.
+Deny: /404.html
 Deny: /bot.html
 Deny: /channel.html