campsite vs camping ground

campsite and camping ground both are nouns.

Word	Noun	Adjective	Verb	Adverb
campsite	Yes	No	No	No
camping ground	Yes	No	No	No

As nouns, campsite and camping ground are synonyms defined as:

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

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

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