The Canada 2021 Census population was 143,680 and the area covers 44,449.49 square kilometres.

The only other city is Merritt; other municipally-incorporated communities include the District Municipalities of Logan Lake, Barriere and Clearwater and the Villages of Chase, Ashcroft, Cache Creek, Clinton and Lytton, and also the Mountain Resort Municipality of Sun Peaks.

The region is named indirectly for the Thompson River by way of the traditional regional names of "the Thompson Country" and "the Nicola Country"; the Nicola Country was named for Chief Nicola and was originally "Nicola's Country", where he held sway; he is also the namesake of that river.

[5] The region is unique in Canada as it consistently holds around some of the hottest summer temperatures in the country, while also containing an area around Ashcroft that may be the only arid climate in Canada.

See List of provincial parks of Thompson-Nicola Regional District.