December. In 1856, Steen negotiated an agreement with Cochise, chief of the Chiricahua Apaches, allowing settlers to cross Apache land while traveling to California. In 1857, Steen helped establish Camp Moore near present-day Rio Rico, Arizona. In 1858, Steen established Fort Buchanan in the newly acquired Gadsden Purchase (near present-day Sonoita, Arizona), and became the post's first commander. He hoped the outpost would deter Chiricahua Apache raids in the Sonoita Valley area. Later that year, he escorted a survey party led by Lieutenant Edward Beale along a proposed road route from Fort Smith, Arkansas to the Colorado River. During the trip, Steen's Buttes in Caddo County, Oklahoma was named in his honor. Steen then led six companies of cavalry into Utah as the Mormon War was coming to a close. Oregon By 1860, Steen was posted in Oregon. On 28 March of that year, General William S. Harney ordered him to lead an expedition from Fort Dalles to Harney Lake, a distance of . Steen's party followed the Walla Walla road to the mouth of the Deschutes River. He then turned south passing through the Ochoco highlands and the Trout Creek area before exploring the upper Deschutes River country. Near Pilot Butte, Steen turned east toward Harney Lake conducting road survey work along the way. While en route, another Army survey party led by Captain Andrew J. Smith was attacked by Indians north of Harney Lake. Steen immediately abandoned his survey work and proceeded to the Harney Lake where he joined Smith and his party. To protect the survey teams in the area, Steen established Camp Union on Silver Creek, north of Harney Lake. On a reconnaissance expedition from Camp Union, Steen explored the country along the Donner und Blitzen River, south of Harney Lake. After a skirmish with Paiute Indians in that area, he chased the Indians over a rugged peak that Hudson's Bay Company trapper, John Work, called Snow Mountain. After Steen and his men crossed the mountain in pursuit of the Indians, the peak became known as Steens Mountain. In late 1860, Steen was given command of Fort Walla Walla in the Washington Territory. He remained there until the outbreak of the American Civil War. Civil War In April 1861, Confederate force attacked Fort Sumter, initiating the Civil War. On 3 August 1861, Steen was assigned to the 1st Cavalry Regiment and ordered to return to the