Fort Platte was a stronghold and trading post in the upper Platte River Valley in the eastern part of the U.S. state of Wyoming established by Lancaster Lupton that was active between 1840 and 1846. The fort competed with Fort Laramie which was only one mile away and quickly surpassed it due to a superior supply system. In 1842, due to economic losses, Lupton had to sell the fort and it was bought by the successful fur trading firm who managed it from 1843 to 1845. In 1845, Pratte and Cabanné moved operations to Fort Bernard to try to capture traffic traveling west on the Oregon Trail before it reached Fort Laramie.