Fort Selden, Military fort in Radium Springs, New Mexico, US.

Fort Selden is a ruin of an adobe fort built from 8 May 1865 by detachments of the 1st California Cavalry, 1st New Mexico Infantry and 1st California Veteran Infantry on the east bank of the Rio Grande at Radium Springs, New Mexico. Surviving wall stubs trace the layout of the post, which stood 12 miles north of Las Cruces in Doña Ana County.

The post was established in 1865 to protect settlers and travelers moving along El Camino Real during a period of conflict with Apache groups. It stayed active until 1891, when it was abandoned and gradually fell into ruin.

The 125th U.S. Colored Infantry, African American soldiers from Kentucky, occupied the fort from 1866, and later the 9th and 10th Cavalry, known as Buffalo Soldiers, were assigned here. Nine Buffalo Soldiers earned the Medal of Honor while serving in New Mexico Territory. The site's name comes from Paraje de Robledo, a camp named for Pedro Robledo, who died on Juan de Oñate's 1598 expedition and was buried there.

The site sits in an open desert with little shade, so sun protection and water are worth bringing before you start walking. Marked paths and information signs guide visitors through the different areas of the former post.

The future General Douglas MacArthur spent part of his childhood here in the 1880s while his father was in command of the post. It was one of the first military settings he knew up close, long before he led armies himself.