Downtown LA's own prefix
Los Angeles has used 213 since 1947, and it now centers on the downtown core.
It is the code of the towers on Bunker Hill, the garment and flower markets, the lofts of the Arts District and the offices around the civic center. Businesses serving this dense, fast-moving part of the city use 213 to show they are right in the middle of it. For callers, it signals someone who knows DTLA, not just greater LA.