Sommers Ranch homestead Teacher Tracy Hughes and some of her students read the interpretive sign at the Sommers Ranch homestead. The homestead is being developed as a living historical site to interpret the homestead era in the Upper Green River Valley, between 1907 to 1957. The site is on the National Register of Historic Places and is a Wyoming Centennial Ranch. It is being managed cooperatively between the Sublette County Historical Society, Green River Valley Museum, and siblings Jonita and Albert Sommers.