Best state for a very left person?

Pretty much any state on either coast. Generally speaking the US is blue around the edge and red in middle. The most liberal state in the country is Vermont (home of Bernie Sanders). Closely followed by Massachusetts, New York, California, Oregon and Washington.

You are not looking for a state as much as a city. NYC, Philly, LA, SFO, Portland, Seattle will mostly fit the bill. Many 'liberal' states are heavily influenced by the largest cities which tend towards liberal/progressive. You would be stunned how conservative large swaths of CA are and Vermont is liberal in a very unique way. VT is about the whitest state in the union. It has a huge % of gun owners. Although, not coincidentally, as Vermont's population became less rural, it became more liberal. This also has a lot to do with migration in from other liberal places like NYC and Boston.

California

I live in rural western Washington. It is predominately Liberal here even in rural areas. A lot of people came here is the seventies to get away. In my neighborhood its a lot of old hippies. You see Trump signs occasionally, but he doesn't have a chance with this crowd.

It depends, are you "very left" or "very liberal"? You used both, so I'm not sure. If you're "very liberal" go to California, Colorado, or New York. If you're "very left" go to Washington, New Mexico, or Vermont.

California or Massachusetts. Vermont is also good.