On Oregon Highway 86 in Hell's Canyon at Oxbow, across from an Idaho Power Station (and managed by Idaho Power), this was a handy place to stay to be close to a boat launch for a rafting trip we had booked. 

There are tiny campsites (maybe the smallest I've seen) and lovely large campsites here. We lucked out and had reserved a big one on the lawn instead of a little one against the rock wall. We were near the power station but we didn't notice it much due to the trees and stream.

There is shade! This was nice considering it gets hot in Hell's Canyon. Even being next to the river and in a rare shady spot in the canyon, the after-dark temperature was in the upper 80's when we stayed here in early August 2020. They water the lawn at night to keep it green, so heed those "sprinkler - do not camp past this point" signs. The bathrooms look nice online (inc. showers), but we camped here during 2020, so we had a row of sunbaked port-o-potties to contend with.

The location was super practical for our needs, our spot was spacious,  and the canyon is beautiful, but due to the heat I probably would pick a place higher up on the canyon rim or closer to Halfway, OR to camp if camping were the main goal (especially in August).

Fair amount of bugs, but that's not specific to this campground. 

Some stats, according to the Idaho Power website: Day use in the park is free. 59 RV sites with water and electric hookups(30-amp); 10 tent sites with shared water; Picnic area with tables Fire rings; Additional vehicle and boat trailer parking available; Public pay phone (phone card required for non-local calls); Boat launch and docks located approximately one-half mile downstream of the park, on Homestead Road

Copperfield was a mining town known as “the rowdiest town in Oregon” in the early 1900s. Fire destroyed the town in August 1915. The park was built in 1965 on the old town site of Copperfield, Oregon. (https://www.idahopower.com/community-recreation/recreation/parks-and-campgrounds/copperfield-park/)