diff --git a/share/man/man4/route.4 b/share/man/man4/route.4
index 96f3a5b022da..5367804e8492 100644
--- a/share/man/man4/route.4
+++ b/share/man/man4/route.4
@@ -318,6 +318,12 @@ Specifiers for which addresses are present in the messages are:
 .Xr sysctl 3 ,
 .Xr route 8 ,
 .Xr rtentry 9
+.Pp
+The constants for the
+.Dv rtm_flags
+field are documented in the manual page for the
+.Xr route 8
+utility.
 .Sh HISTORY
 A
 .Dv PF_ROUTE