depends on your steam install path, usually here:
C:\Program Files\Steam\SteamApps\common\Nuclear Dawn\nucleardawn\maps

you don't need to delete those maps unless you want to clear some space

thanks for the reply. i actually looked there and I don't see anything that looks like 3rd party.

I subscribed to the "ocean" map in workshop. it was like a 20MB download. but I don't see any files with appropriate size, date, or for that matter, name.

(and no offense intended to the creator of "ocean", btw, in removing your map. I just wanted to download something small as a test, and since it said "work in progress" i figured it would be smallish. i'll be glad to check it out again when it's done ;))

steam downloads workshop content to a temporary folder, you need to run the game at least once. the game copies content to appropriate folder at start. in ND case it is "maps" folder.

ah ok the game was running when i subscribed so it probably didn't do the move yet. thanks!

also, be aware that workshop works badly. sometimes steam doesn't download the map fully, e.g. from 90 MB map it can download 20 MB and say "Completed", then you run the game and it all crashes hangs etc etc

same with l4d2 workshop, I'm suprised Valve can't fix it for a so long time.

hmm ... never had that happen, but I will look out for it. (I don't really use workshop that much.)

but I did notice that if you unsubscribe an item while it is still downloading, steam doesn't seem to recover very gracefully from that. it stopped DLing but it just kept the item in the DL queue.