Washington State is another good candidate. Split it down the Cascades and you have ultra-liberal coast and traditional conservative inland.
Would like to see Oregon split like this also. We (Oregon) are actually a mostly red state. Problem is, most of the population is in Portland, Salem and Eugene, which is where the majority population, mostly blue, resides.
Don’t just split Washington. Recombine Oregon and Washingtion into Washegon and TransCascadia.