From the record
“Fort Steele, also known as Fort Fred Steele, was established to protect the newly built Union Pacific Railroad from attacks by Native Americans during construction of the transcontinental railroad in the United States. The fort was built in 1868 where the railroad crossed the North Platte River in Carbon County, Wyoming.”
Wikipedia article Fort Fred Steele State Historic Site, CC BY-SA 4.0.
One of 43 National Register listings published here for Carbon County · listed in 1969 · category: Site.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service