Linguistically, the Umatilla people spoke a tongue that was part of the Sahaptin division of the Penutian language family — closely related to other peoples of today's Eastern Oregon, Eastern Washington, and the Idaho panhandle. These included the Nez Perce, Cayuse, Walla Walla, and the Yakima. These peoples were ravaged by smallpox and other diseases during the first half of the 19th Century and their populations depleted.
The Umatilla share land and a governmental structure with the Cayuse and the Walla Walla tribes as part of the Confederated Tribes of the Umatilla Indian Reservation. Their reservation is located near Pendleton, Oregon near the Blue Mountains.
A number of places and geographic features have been named after the tribe, such as the Umatilla River, Umatilla County, and Umatilla National Forest. McNary Dam was almost named Umatilla Dam.
The impoundment of the Columbia River behind the next dam downriver, John Day Dam, is called Lake Umatilla.
- "Umatilla," in Barbara A. Leitch, A Concise Dictionary of Indian Tribes of North America. Algonac, MI: Reference Publications, Inc., 1979; pp. 490-491.
- Humphrey, Seth K (1906). The Indian dispossessed. Little, Brown and Co.Available online through the Washington State Library's Classics in Washington History collection