Cities out West in the States tend to be less dense because they were founded by people who generally had horses/wagons already to get there and because they we

Cities out West in the States tend to be less dense because they were founded by people who generally had horses/wagons already to get there and because they were founded closer in time to the invention of the automobile, so their infrastructure was less solidified by the time it was introduced and thus they've adapted more to cars with a broader sprawl and less vertical buildup. Of course this isn't true of all cities in the Western US, but as a general trend it holds up.