Stephen H. Long.
Cantonment Martin was the first military post in Kansas under U.S. government authority. The post was established on Isle au Vache, or Cow Island, in October 1818. Located on the island in the Missouri River within present-day Atchison County, Kansas, Captain Wyly Martin established it with a detachment of the Third Rifle Regiment as a supply base for Major Stephen H. Long’s Expedition of 1819-1820.
Major Long and his explorers reached the site on August 18, 1819, aboard the Western Engineer, the first steamboat to travel up the Missouri River. Before leaving Cow Island for his famous scientific journey into the Rocky Mountains, Major Long held a peace powwow with 13 Osage and 161 Kanza Indians.
Captain Wyly Martin and his men stayed behind to build the post when Long and his explorers headed westward. The fort was erected of cottonwood logs, and the regiment spent the Winter of 1819 there. John O’Fallon, a prominent citizen of St. Louis, Missouri, served as the post sutler. Captain Martin intended to vacate the cantonment early in the spring of 1819 and continue his march westward. However, his supplies failed to arrive as expected, and he remained at the post until the main body of the expedition under Major Long returned in July. After the remainder of Long’s Expedition returned in October 1820, the camp was abandoned. In 1826, the First United States Infantry temporarily occupied it and renamed it Camp Croghan.
By 1832, several Missouri River floods had washed away all buildings on the island. The island was not occupied again until the Civil War. On June 3, 1861, members of the First Kansas Volunteers used it as a base of operations against the Confederate town of Iatan, Missouri, which was on the opposite side of the Missouri River.
©Kathy Alexander/Legends of America, updated October 2026.
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