#1 ADX Florence Supermax Prison
The ADX Florence Supermax Prison is said to house the most dangerous criminals in the United States. Located in Fremont County, Colorado it has a population of just 439 inmates currently but has the tightest security in the country. Many inmates here commit suicide due to the complete isolation from everyone and everything including other inmates as well as guards. The Alcatraz of the Rockies first opened its doors in 1994.