This post was a temporary post established by Crook in 1876 and has the odd distinction of being a fairly significant temporary base built within just a few miles of an abandoned fort, Ft. Reno. The post was built in September 1876 as a temporary supply depot for Crook's troops operating out of Ft. Fetterman, which was quite distant (I'd guess 80 or more miles).
I'm sure I've read in War Path and Bivouac about Fetterman's troops crossing this area, but I don't recall much what Finerty wrote about it, and I frankly can't recall whether he mentioned Ft. Reno or Ft. Phil Kearny being dispiriting due to having been burnt down. I sort of recall it was Ft. Reno, but I may be off base. At any rate, it's curious that he chose this spot. Reports indicate that some adobe walls were left standing but broken down when he arrived. If so, nothing of adobe walls remains today. Crook chose to locate his post some three miles back down the Bozeman Trail.
Reno Cantonment was hastily thrown up but a stunning 42 buildings were built in a mere three months. The post was then used as a supply point for troops operating in the Powder River Basin in the winter of 1876, showing perhaps that Patrick Conner's choice of nearly the same spot was a strategically necessary one. When Crook located here in 1876 his supply depot was even more isolated than Ft. Reno had been, however, as the Oregon Trail stations had been closed and the nearest base was Ft. Fetternman.
The post supported operations that winter, most notably the campaign by Ranald Mackenzie that resulted in the Dull Knife Fight. A Lt. McKinney was killed in that battle and the post renamed after him, but this post proved very difficult to supply with lumber, forage and water, so the decision was made to abandon it in 1878 in favor of a new location, also named Ft. McKinney (and now the Wyoming Veteran's Home) near Buffalo Wyoming. Perhaps ironically, the new Ft. McKinney was much closer to the old Ft. Phil Kearny than this location.
Nothing is left of Reno Cantonment. It was only occupied for two years, but it was fairly substantial. It's all gone now.
The cottonwood line is the Powder River.