https://en.wikipedia.org/wiki/Rent_regulation#United_States
As of 2018, four states (California, New York, New Jersey, and Maryland) and the District of Columbia have localities in which some form of residential rent control is in effect (for normal structures, excluding mobile homes).[5][6] Thirty-seven states either prohibit or preempt rent control, while nine states allow their cities to enact rent control, but have no cities that have implemented it.[5][6]