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How many people live in Cascadia? (Spoiler: 21M. But let’s break it down.)

sightline.orgTwenty-one Million Cascadians: An Overview | Sightline InstituteWho is Cascadia? A new series on the bioregion’s people.

Sightline Institute

@sightline.org

Cascadia is a bioregion. We mark the borders by watershed, stretching from the Rockies to the Pacific and from Alaska to California. Those aren’t political borders, which make them hard to tabulate.

Sightline Institute

@sightline.org

Resident Data Guy @jayleetx.com took up the task of counting the people who live here: all 21,561,819 (ish) of them.

8/10/26, 3:45 pm0 reposts7 likes

And it's growing.

Unsurprisingly, the population centers are Cascadia’s largest urban areas. The top ten most populous jurisdictions are home to 10.8 million people, while the other half of the region is spread out across the other 165 jurisdictions. More data: www.sightline.org/2026/10/08/t...