Peaceful Valley Ranch, Historical ranch in Theodore Roosevelt National Park, North Dakota, US

Peaceful Valley Ranch comprises nine main structures. Benjamin Lamb built the 1+1⁄2-story frame ranch house, with enclosed porches on the front and north sides and a log extension at the rear. A one-story log lodge for dude ranch functions stands north of the house, and a 1905 log barn lies to the east. The complex includes an extensive corral.

Eldridge G. Paddock, a former guide for the Northern Pacific Railway and George Armstrong Custer, built a cabin a quarter mile south of the site in 1883. Benjamin S. Lamb, a 22-year-old rancher, bought the range rights in 1885 and built the main house. The Olsen family ran it as a dude ranch from 1918 and sold it to the National Park Service in 1936.

The ranch served as a gathering place for visitors seeking horseback exploration of the badlands landscape. It reflects how ranching families in this region adapted their homesteads to welcome travelers.

The ranch lies about 3 miles (4.8 km) from Medora in the South Unit of Theodore Roosevelt National Park. The complex of nine main structures, including the 1905 log barn and the corral, is reached from the main park road; the Paddock cabin site is near the road junction. The grounds are open to walkers, and the buildings are best viewed from outside.

This ranch house is the only original homestead structure surviving in the South Unit of the park while maintaining its Victorian design among predominantly log-built buildings. Its architectural style sets it apart from the typical log cabins found throughout the area.