campground vs campsite

campground and campsite both are nouns.

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

As nouns, campground and campsite are synonyms defined as:

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

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

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