Three Crossings on the Sweetwater River, so called because the trail crossed the stream three times within ¼ mile. Located 14 miles from Split Rock Station and 12 miles from Ice Springs Station south of the Sweetwater River. A telegraph and stage station of the 1860′s, it was to this station in 1860 that Bill Cody, 15 year-old Pony Express carrier, rode from Red Buttes on the Platte, 76 miles away. There he found that the rider of the 85-miles stretch to Rocky Ridge had been killed. Cody thereupon, without resting, rode to Rocky Ridge and returned to Red Buttes, with eastbound mail, on time. This 322-mile ride is the longest on the records of the Pony Express.

http://www.expeditionutah.com/featured-trails/pony-express-trail/wyoming-pony-express-stations/

Sources generally agree on the identity of this site as a Pony Express station, probably because it appeared on the 1861 Overland Mail Company contract.  However, Gregory Franzwa identifies separate stage and Pony stations at Three Crossings, locating the Pony Express station site west of the stage station.  According to one source, an English Mormon couple with the last name of Moore managed station operations at Three Crossings, a home station for both stage lines and Pony Express riders.

http://www.nps.gov/parkhistory/online_books/poex/hrs/hrs6a.htm#76