campsite vs campground

campsite and campground both are nouns.

Word	Noun	Adjective	Verb	Adverb
campsite	Yes	No	No	No
campground	Yes	No	No	No

As nouns, campsite and campground are synonyms defined as:

campsite and campground: a site where people on holiday can pitch a tent

Other synonyms of campsite include bivouac, camping area, camping ground, camping site, encampment.

campsite (noun)	campground (noun)
a site where people on holiday can pitch a tent	a site where people on holiday can pitch a tent