The Regional District of Okanagan-Similkameen (RDOS) is in southern British Columbia, adjacent to the U.S. state of Washington. It is bounded by Fraser Valley Regional District to the west, Thompson-Nicola Regional District and Regional District of Central Okanagan to the north, Regional District of Kootenay Boundary to the east, and by Okanogan County, Washington to the south. At the 2011 census the population was 80,742. The district covers a land area of 10,413.44 square kilometres (4,020.65 sq mi). The administrative offices are in the City of Penticton.
- 2011: 80,742 (+1.6%)
- 2006: 79,475 (+3.7%)
- 2001: 76,635 (+0.9%)
- 1996: 75,933
RDOC comprises six municipalities and eight rural electoral areas designated Electoral areas A - H. The municipalities of RDOC are Penticton, Summerland, Osoyoos, Oliver, Princeton, and Keremeos.
- Okanagan-Similkameen A
- Rural areas surrounding Osoyoos, including Anarchist Mountain to the east between Rock Creek and Osoyoos.
- Population: 1,892
- Okanagan-Similkameen B
- The valley of the Similkameen River from Cawston downstream to Chopaka, at the US border.
- Population: 1,140
- Okanagan-Similkameen C
- Rural areas surrounding Oliver, including the Mount Baldy Ski Area (though there are no residents there).
- Population: 3,473
- Okanagan-Similkameen D
- Rural areas and unincorporated communities south of Penticton, including Kaleden and Okanagan Falls.
- Population: 5,717
- Okanagan-Similkameen E
- Rural areas and unincorporated settlements to the northeast of Penticton including Naramata.
- Population: 1,844
- Okanagan-Similkameen F
- Rural areas west of Summerland and northwest of Penticton.
- Population: 2,100
- Okanagan-Similkameen G
- Rural areas of the middle Similkameen Valley surrounding Keremeos, including Hedley.
- Population: 2,314
- Okanagan-Similkameen H
- Rural areas and unincorporated communities in the upper Similkameen Valley, including Tulameen and Coalmont.
- Population: 1,768
Coordinates: 49°25′00″N 120°00′00″W / 49.41667°N 120.00000°W