This doesn’t include the apparently over 350,000 Home Owner Associations in the USA that are effectively another layer of local government with the powers to tax and regulate like other special districts
Citing Tabarrok, Alexander (2002). "Market Challenges and Government Failure: Lessons from Voluntary City". In Beito, David T.; Gordon, Peter; Tabarrok, Alexander (eds.). The Voluntary City: Choice, Community, and Civil Society.