This gem turned up recently while re-housing our lantern slide collection. It doesn’t look like much from here. In fact it was labeled “unidentified town.”
How times have changed. The wide open plains in this photo are now residential neighborhoods (and there are a lot more trees)
(WSA H55-53/220, colored lantern slide)
But if you take a closer look (or scan it at an absurdly high resolution) the image gets a bit more interesting.
Detail of the lantern slide above. Once the buildings can be identified, it is pretty clear that you are looking south down what would be Capitol Avenue at the back of the Capitol Building.
(WSA H55-53/220)
This picture happens to be of Cheyenne, taken from north of the Capitol Building looking back towards town. The photo was probably taken between 1905 and 1910.
The large building just to the left of the Capitol Building is the Convent and Academy of the Holy Child Jesus, run by sisters from the Society of the Holy Child Jesus. The building was completed in 1886, the same year construction began on the Capitol Building, and was replaced in 1952 by the St. Mary’s Grade School building. This lot has since been transferred to the State of Wyoming and is currently being used as a parking lot with the eventual plan to construct a State office building on the site.
The Masonic Temple, built in 1903, is clearly visible on the right. The current roof line of the building is a bit different from this original one, thanks to a fire around 1911.
The road on the far right of the photo is Carey Avenue, thought at the time it was known as Ferguson Avenue. Many of the cattle barons built their mansions along this road, earning it the moniker “Millionaire’s Row.” If you were to follow this road to the north out of this frame, you would find Frontier Park, home of Cheyenne Frontier Days.
Lantern slides like this one were designed to be projected onto a screen or wall. The blue and green tinting of the slides was an attempt to make it look more realistic in the era before true color photographs.
Wyoming Postscripts 
What a fine discovery! The Masonic Temple was built in 1902-3 so your time frame for the picture must be very close. It’s interesting to me that the blowup doesn’t make the mansions of Idelman, Kelly and Whitcomb appear.
Indeed, everything looks “vacant” on the west side of Carey. Do you suppose the stand of trees visible to the NE of the Capitol Bldg is the site of Lakeview Cemetery? Thanks, Clint Black