Tom Sun Ranch, Historic cattle ranch in Sweetwater Valley, Wyoming, US

Tom Sun Ranch is a historic cattle ranch along the old Oregon and Mormon trails on Wyoming Highway 220, about 6 miles west of Independence Rock. At its 1960 landmark nomination it covered 4,160 acres (16.8 km²) and was among the best-preserved ranches of the cattle-ranging period. Some ranch buildings now serve as a visitors' center for nearby Martin's Cove.

Tom Sun Ranch was built by Thomas Du Beau Soleil, a French-Canadian frontiersman known as Tom Sun who became a pioneer cattleman; during the 1870s and 1880s it typified medium-sized ranching operations in cattle country. It was declared a National Historic Landmark on December 19, 1960, when it was one of the best preserved ranches of the cattle ranging period and measured 4,160 acres. The Sun family held it for four generations until 1996, when it was sold to the Church of Jesus Christ of Latter-day Saints.

The place shows how ranchers lived and worked in the 1800s, with buildings that reflect the daily rhythm of frontier life in this remote area. Visitors can walk through the structures and understand how families and workers shared this isolated landscape.

The site is managed as a visitor center with displays about ranching and pioneer history. Plan for flat terrain and prepare to walk between several buildings to see the full property.

The ranch stayed in the Sun family for four generations until 1996, when it was sold to the Church of Jesus Christ of Latter-day Saints. Some ranch buildings now serve as a visitors' center for nearby Martin's Cove, a Mormon historic site. Parking lots and landscaping added since then do not match the original setting, though publicly owned sections keep their historic character.