Multnomah County is the largest,, and most progressive county in Oregon, encompassing 807,555 people (as of 2017), 13.9% of whom are foreign born, and 520,152 registered voters. Elections statewide are won when Multnomah County performs at 80%, which it usually does. Unfortunately, the story of Multnomah County is really a Tale of Two Counties. Multnomah County is split down the middle. Many of the people who once resided on the West side of the county in Portland have been pushed to cities further out, which have been gentrifying at alarming rates, particularly in East County. For reference, the median gross rent in Multnomah County is now $1,013/month.
Sources: U.S. Census Bureau, OR Secretary of State Elections Division