The Regional District of East Kootenay (RDEK) is a regional district in the Canadian province of British Columbia, Canada. In the 2016 census, the population was 60,439. Its area is 27,542.69 km2 (10,634.29 sq mi). The regional district offices are in Cranbrook, the largest community in the region. Other important population centres include the cities of Kimberley and Fernie, and the district municipality of Invermere and Sparwood. Despite its name, the regional district does not include all of the region known as the East Kootenay, which includes the Creston Valley and the east shore of Kootenay Lake.

Cranbrook is a city in southeast British Columbia, Canada, located approximately 10 km southwest of the confluence of the Kootenay River and the St. Mary's River. It is the largest urban centre in the region known as the East Kootenay. As of 2016, Cranbrook's population is 20,499 with a census agglomeration population of 27,040. It is the location of the headquarters of the Regional District of East Kootenay and also the location of the regional headquarters of various provincial ministries and agencies, notably the Rocky Mountain Forest District.