Imagery of an American West that isn’t coming back. Taken from the 1858 work “Diary of a Journey from the Mississippi to the Coasts of the Pacific With a United States Government Expedition.” Volumes I and II. Balduin Möllhausen, artist.

As with so many of these, they would have chromolithographs or other types of prints done up to sell after the expedition ended. Sometimes they would then turn the prints into a book. Sometimes not. Some of these are in the New York Public Library collections but these images are from the Internet Archive who appear to have more of them. The expedition itself was in 1853.