diff --git a/changes/bug19728 b/changes/bug19728
new file mode 100644
index 000000000..98ba34290
--- /dev/null
+++ b/changes/bug19728
@@ -0,0 +1,3 @@
+  o Directory authority changes:
+    - The "Tonga" bridge authority has been retired; the new bridge
+      authority is "Bifroest". Closes tickets 19728 and 19690.
diff --git a/src/or/config.c b/src/or/config.c
index 908f098ce..4b065a005 100644
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -910,8 +910,8 @@ static const char *default_authorities[] = {
   "dizum orport=443 "
     "v3ident=E8A9C45EDE6D711294FADF8E7951F4DE6CA56B58 "
     "194.109.206.212:80 7EA6 EAD6 FD83 083C 538F 4403 8BBF A077 587D D755",
-  "Tonga orport=443 bridge "
-    "82.94.251.203:80 4A0C CD2D DC79 9508 3D73 F5D6 6710 0C8A 5831 F16D",
+  "Bifroest orport=443 bridge "
+    "37.218.247.217:80 1D8F 3A91 C37C 5D1C 4C19 B1AD 1D0C FBE8 BF72 D8E1",
   "gabelmoo orport=443 "
     "v3ident=ED03BB616EB2F60BEC80151114BB25CEF515B226 "
     "ipv6=[2001:638:a000:4140::ffff:189]:443 "