I first saw this place a couple weeks ago on that new show on HGTV: You Live In What?!
The Carnegie library-turned-home is located in Sterling Colorado which is a small town on the eastern flat lands of Colorado. (No, not all of Colorado is mountainous – we have half of Kansas in our state!)
Anyway, Sterling was one of those small towns in America that benefited from the philanthropy of Industrialist Andrew Carnegie when the townsfolk received funds to build a public library in 1916.
The library was sold privately (probably when a newer, larger and wheelchair accessible space was needed) and the new owner did an exquisite restoration job and conversion into a residence.
For a few years, the old library was even used as a bed & breakfast, and also housed a counselling business.
It is now a private residence again but I was still able to find a few interior pictures of the building on-line.