diff --git a/ipv6/us.cidr b/ipv6/us.cidr
index 42f7d8bb9..e2c95bc8a 100644
--- a/ipv6/us.cidr
+++ b/ipv6/us.cidr
@@ -985,6 +985,7 @@
 2602:819:9000::/40
 2602:819:a000::/40
 2602:819:b000::/44
+2602:f878::/40
 2602:f879::/40
 2602:f87a::/36
 2602:f87c::/40