For some, the old image of the nation’s white Northwest — sometimes called Cascadia, a piney, mythical homeland free of immigrants and minorities — lives on as a place worth defending, even though it is now largely a mirage, Mr. Blazak said. And many Oregonians refuse to study or acknowledge the legacy of their history, from the state’s founding to the rise of its Ku Klux Klan in the 1920s to the gentrification and displacement of communities of color today, he said.

Language incorporated by popular referendum in the 1857 State Constitution prohibited blacks from living here, owning property or entering legal contracts, and made Oregon the only non-slavery state admitted into the union with a so-called exclusion clause. The provision was never strictly enforced, historians said. But some racist language remained in the Constitution through as late as 2002. Oregon’s population is still only 2.2 percent black.

“When I talk to people and say Oregon was formed as this whites-only state, there’s this look of ‘How that could possibly be?’” Mr. Blazak said. “People are just shocked that this is our history.”

That history still endures. Skinhead groups rose to prominence here in the 1980s, and last year, a man spouting what witnesses said were racist and anti-Muslim language stabbed two people to death on a transit train.

Oregon for many years deliberately sought to cordon itself off from the rest of the country, and by some measures succeeded. In the early 1970s, Gov. Tom McCall famously urged Americans to come and visit — with a caveat: “But I also ask them, for heaven’s sake, don’t move here to live.” (Some have speculated that Mr. McCall was using reverse psychology: Tell people not to come and they’ll immediately think they’re missing out on something great.)