Pitch a tent on American college grounds (6)
I believe the answer is:
campus
'college grounds' is the definition.
(university or college site)
'pitch a tent on american' is the wordplay.
'pitch a tent' becomes 'camp' (I've seen this before).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'american' becomes 'US' (United States).
'camp'+'us'='CAMPUS'
(Other definitions for campus that I've seen before include "academic haunt" , "University premises" , "educational location" , "buildings in Nottingham, say" , "student quarters" .)