Hollywood isn’t a city, county, or political jurisdiction. It’s boundaries aren’t even clearly defined.
It’s not so much dirt poor as it’s working class.
And when you see or hear the term “Hollywood” in popular discourse, it’s usually a metonym for the big studio film industry, a lot of which doesn’t operate in Hollywood proper anymore. (However, the commercial part of Hollywood is being revitalized.)
The City of London – population about 9,200, a figure which has roughly doubled in the last 40 or so years.
Salem, Mass. 40,407
I love the odd old museum there, full of sailing day sailors’ treasures from foreign lands.
And of course the witch pyre every feast day 
After a casual glance at this thread, I’ve noticed that Sturgis, SD (population 6,132) is missing - home of an incredibly massive, and well-known, annual biker rally/party. It’s estimated that the town’s population is increased by over 500,000 people when the event is in progress.
If you have been to the Sturgis rally or a similar event, you will know the reasons for the implied notoriety.
Bethlehem: pop <30,000.
( Or a couple of dozen 
)
It’s not there anymore, at least not officially, but at its peak, New Rome, Ohio had about 60 residents. It was probably the most notorious speed trap in the US.
And another one. Centralia, PA has nine residents. The rest of the town was chased out of town because of a coal fire that has been going since 1962. The state claimed eminent domain in 1992 to encourage residents to leave and the Post Office revoked the town’s zip code in 2002. Centralia is a stellar, almost textbook, example of a massive environmental disaster.
Robin