Superboy and Supergirl sometimes travel to the 30th Century to work with the Legion of Superheroes. Aren't there any potential descendants they may meet, and if so do they ever meet (I don't think in any Silver Age stories)? I'm aware of the (silver age) story "The Superman of the Future" (Action Comics 256) which has an Ultra Superman from the year 100,000, but don't know much about this story so am not sure if this was actually a descendant of the present day Superman.
2 Answers
Yes, there was Laurel Kent, who was originally a descendant of Superboy and whom he met. In her first appearance she says she looks like the woman he is destined to marry (i.e., Lois Lane)
She was later retconned to have been a Manhunter android all along.
Descendants of Superman? You're aware of Action Comics #256 and its future references, but I infer from your question that you are not aware of Superman #181 (1965). The splash page of the story sums it all up...
There is no warning or blurb that this is an "Imaginary Story". Only the start of a "New Series!", so it as canon as the DC Silver Age gets.
A new series that didn't gain much traction, though. Superman of 2965 appeared in Action Comics #338 and #339 (1966), then World's Finest #166 (1967) (with future Batman!). Those are all the Silver Age appearances I know of. (However, another one of those endless DC Universe reboots featured the future Superman in a two-part 1998 story in Superman #136-137)