Kooskia developed within the Nez Perce Indian Reservation after the federal government divided the 756,960-acre reservation into family-sized allotments between 1889 and 1893, leaving more than 70 percent unallotted; those lands were ceded back to the government, declared surplus, and opened to settlement in 1894. As land claims were filed, 104 acres at the confluence of the Middle Fork and South Forks of the Clearwater River were reserved for a townsite, and in 1897 the town of Stuart was surveyed and named for James Stuart, a prominent Nez Perce surveyor, furniture store merchant, Forest Service ranger, and member of the town's first Board of Trustees. After a railroad line was laid through the town in 1900, the depot was called Kooskia because Stuart was already in use elsewhere on the line, and the town officially adopted the name Kooskia in April 1902. Although Koos-koos-kee later came to be thought of as a Nez Perce term meaning clear water, P.B. Whitman recorded that Lewis and Clark had misunderstood the Nez Perce words Koots-koots-kee, meaning this is the smaller, when the Nez Perce were distinguishing the smaller visible stream from the larger Snake; Kaih-kaih-koosh is the correct Nez Perce word for clear water. Kooskia also became a Forest Service community after the Bitterroot Forest Reserve was designated in 1897, and many local residents worked in the country between there and the Montana border. Among the area's notable Forest Service figures was Frank Fenn, whose varied career included military, legal, political, and forestry service; after service in the 1877 Nez Perce conflict and in the Idaho First Volunteer Infantry during the Spanish-American War in the Philippines, he entered the forest reserve system, became Idaho superintendent, and in 1907 became the first supervisor of Clearwater National Forest. His career lasted more than 20 years, several landmarks bear his name, and he was buried in Kooskia's Pine Grove Cemetery after his death in 1927.