From the record
“Fort Bridger was originally a 19th-century fur trading outpost established in 1842, on Blacks Fork of the Green River, in what is now Uinta County, Wyoming, United States and was then part of Mexico. It became a vital resupply point for wagon trains on the Oregon, California, and Mormon Trails.”
Wikipedia article Fort Bridger, CC BY-SA 4.0.
One of 13 National Register listings published here for Uinta County · listed in 1969 · category: Site · built in 1928.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service

