If you have kids, and/or just like to immerse yourself in the history of the area you're camping in, Fort Stevens State Park is the right place. 

For the casual state park camper: Tons of campsites with a variety of size and accommodation options, rentable cabins and yurts, excellent bathroom and shower facilities, close to the ocean, and bike paths galore. 

For the history buff: The wreckage of the Peter Iredale; year-round military displays at the military museum and information center; the only Civil War-era earthen fort on the west coast; multiple turn-of-the-century, concrete artillery gun batteries; underground tours of a gun battery that served as a World War II command center. Fort Clatsop, the last encampment of Lewis and Clark's Corps of Discovery before embarking on their return trip east to St. Louis.