Long before westward migration to Oregon and California, animals instinctively stopped at the Big Sandy River during migration, and with South Pass just 35 miles east, the river also formed a natural east-west pathway for people. The pathway and river made the area a stopping place for Native Americans and later explorers, including the Mountain Men, and with travel to Oregon, California, and Utah, it became a stop for wagon trains on this part of the Oregon/California/Utah trail. The Donner Party encamped here on July 24, 1846, after deciding to try a new shortcut to California beyond Fort Bridger. Seven miles east of here, on June 28, 1847, the first Mormon wagon train with the Prophet Brigham Young met frontiersman Jim Bridger on the Little Sandy River, and the next day the Mormons rested at the Big Sandy before pushing on to reach the Green River that same day. By 1858, the Big Sandy Mail Station had developed as a site for mail service between the Missouri River and Salt Lake City, and the Central Overland California & Pike’s Peak Express Company, which operated the Pony Express, made it one of the original stops for Pony Express and Overland Stage service. The Pony Express began on April 3, 1860, operated 19 1/2 months, and was then replaced by the Transcontinental Telegraph service, whose line came through this location. Other notable travelers, including Horace Greeley, Sir Richard Burton, Samuel Clemens, known as Mark Twain, and tens of thousands of trail emigrants, used this pathway traveling either east or west, but mainly west.