Located 10 miles from North Platte Station and 12 miles from Willow Springs Station about 200 feet southwest of the Red Buttes Oregon Trail Marker and south of the old Goose Egg Ranch house. Red Buttes Pony Express Station was located on a ridge overlooking the North Platte River at Bessemer Bend. Explorers, fur traders, mountain men and emigrants camped at this site. Although the main route of the Oregon Trail was located a few miles north of this site, many emigrant travelers crossed the North Platte River here for the last time on their trek to the west. They preferred using this favorable ford rather than waiting in line and paying the tolls and ferry fees required at lower crossings. Ample grass, good water and pleasant surroundings made this a favorite campsite for some travelers, since the route to and from the Sweetwater River was three days of rough, dry country and poisonous alkali water. 

Pony Express lore recalls than William “Buffalo Bill” Cody, one of the youngest Pony Express riders at the age of 14, made the longest non-stop ride from this station. Completing his own run of 116 miles between Red Buttes and Three Crossings, he found his relief rider had met any untimely death, causing Cody to ride an extra 76 miles to Rocky Ridge Station. He immediately returned from Rocky Ridge to Red Buttes, completing the route in record time.  http://www.expeditionutah.com/featured-trails/pony-express-trail/wyoming-pony-express-stations/

Sources generally agree on the identity of Red Butte(s) as a C.O.C. & P.P. Express Co. or Pony Express station, also largely because this name appears on the 1861 Overland Mail Company contract.  Franzwa specifically lists Red Buttes as a Pony Express stop on his maps. 

http://www.nps.gov/parkhistory/online_books/poex/hrs/hrs6a.htm#69