The Regional District of Kootenay Boundary (RDKB) is a regional district in the province of British Columbia, Canada. As of the 2006 census, the population was 30,742. The area is 8,095.62 km² (3,125.74 sq mi). The regional district's offices are in the city of Trail. Other major population centers include the cities of Grand Forks, Rossland, and Greenwood, and the villages of Fruitvale, Warfield, and Montrose.