What are some differences in laws between Oregon and Washington?

I was browsing the wikipedias today and came across Oregon’s and Washington’s population density maps.

I heard on the East coast that it’s common practice to hop between states for things like more lax firework laws. I figured something like that (but, y’know, on a bigger scale) must be the reason for so much density in that area around Salem, OR and Vancouver, WA.

I had found that Oregon’s fireworks laws and marijuana laws are more lax, and I found that Washington’s age of consent is 2 years younger.

But I was wondering what other major differences there may be for people to live so close to the borders? or is it just great altitude/weather/precipitation/nature that brings people to that section?