“The most primitive of Yellowstone’s campgrounds and sites, the accommodations are distributed among the banks of the stream, meadow land, and forest.” (Fodor’s Travel)

Slough Creek Campground—elevation 6,250 feet (1905 m)—is located in Lamar Valley near some of the best wildlife watching opportunities in the park. Located at the end of a two mile graded dirt road, this campground is best suited for tents and small RVs. There are plenty of hiking opportunities in the area, including the Slough Creek Trail which begins nearby. Nighttime offers a quiet, unimpeded view of the stars and the possibility of hearing wolves howl.

https://www.nps.gov/yell/planyourvisit/sloughcreekcg.htm

(As rated by Fodor’s Travel)