The LA in the previous comment is likely Louisiana -- where many refineries are based.
Also, CA has its own refineries that have additional blend restrictions (if I am not wrong). You cannot legally sell, gasoline that is refined in LA or TX and sell them in CA gas stations.
You are right -- there are 5 refineries in LA county and 60% of the California capacity. The possibility of them having $1 gallon in CA did not feel real given the taxes and fees per gallon are near or exceed $1.
Also, I'm a little confused: SD and LA are in California, of course.