West coast, here, where mobbed up neighborhoods are something that only exist in the movies.

Last one was probably SF's North Beach, and you'd have to go back to the 1960s. .

Last ones in LA were Boyle Heights and Lincoln Heights, which became Latino neighborhoods not long after Prohibition.

The most mobbed up neighborhood ever out here, or city, actually, was Emeryville, which sits between Berkeley and Oakland, during Elmer "Big Bones" Remmer's reign in the mid 20th century. Remmer was Lucky Luciano's guy and eventually the Genoveses' guy in the bay area. He ran all of the gambling operations in the bay area. He had Emeryville's government in his pocket and ran the town.