United States vs Georgia
City, county, and state operated prisons are covered under Title II of the ADA.
This Supreme Court ruling upheld this position in 2006. A man was imprisoned in Georgia and he was a wheelchair user. He stated that his cell was the same size as other cells meaning that it was so tiny that he could not move around or even turn his wheelchair. He ended up staying in his cell almost 24 hours a day, not being able to join in religious activities or class time that the other inmates were able to take part in. The worst part about it was that he was not given access to medical supplies. He said that a lot of times he had to sit in his human waste because he did not have basic supplies such as catheters nor could he transfer over to a toilet. He also developed pressure sores that were not treated (which if you are a wheelchair user or know about pressure sores, that can be very dangerous).
This case granted Congress more authority over States regarding disability rights. You can read more about the case here: http://www.supremecourt.gov/opinions/05pdf/04-1203.pdf