Fort Lapwai, Military fort in Nez Perce County, Idaho, US.

Fort Lapwai is a former U.S. Army post on the west bank of Lapwai Creek, three miles above its junction with the Clearwater River. Established in 1862 as Camp Lapwai and renamed in 1863, it lies within the Nez Perce Reservation and is part of Nez Perce National Historical Park. Several original structures remain at the site.

Camp Lapwai was established in 1862 by Major Jacob S. Rinearson, 1st Oregon Cavalry, on the order of Brigadier General Benjamin Alvord, to keep white settlers off Nez Perce lands and the Nez Perce from retaliating. Company E, 1st Washington Territory Volunteer Infantry, arrived from Alcatraz that October to build the post, joined by Company F, 1st Oregon Volunteer Cavalry, in November. Renamed Fort Lapwai in 1863, it was decommissioned on June 5, 1884, and turned over to the Indian Service.

The name Lapwai comes from a Nez Perce word meaning "place of the butterflies," for the thousands seen here in early summer. The Northern Idaho Indian Agency moved to the fort site in 1904, and several original structures remain. A tuberculosis sanatorium and preventorium operated on the grounds from 1907 to 1944.

The site is accessible by car via Highway 95 South from Lapwai, requiring several turns to reach the grounds. Visitors should note that on-site facilities are limited and comfortable footwear is helpful for exploring the area.

The name Lapwai comes from a Nez Perce word meaning 'place of butterflies,' referring to the many insects visible during early summer months. This naming preserves part of the original connection between the location and its seasonal natural features.