The list of gas stations in the US are provided by a 3rd party and are not accessible in the editor. There currently isn't a way to add missing stations in the US.

Also, because you asked about it in your UR (I'm pretty sure it was you anyway), the landmark that is there, serves a few purposes (mainly traffic jam suppression for people at the pumps), but doesn't add the station to the list for prices.

I also would like to publicly applaud you for the amazing level of detail in your URs, as most of the ones we get have no information about the problem whatsoever. Thank you very, very much.