Walnut Street Prison Historical Marker 
As the United States began to populate, county lines began to be drawn up for States earning Statehood. 
Sheriffs began to police their Counties, and also be responsible for managing the lower level infractions 
(misdemeanors) within their jurisdictions. Thus, County Jails began to flourish in the United States. Initially, 
many jails were nothing more than parts of a Sheriff’s office, literally, cells in the back room. Today, large 
structures (even multiple structures in a single county) constitute jails in the United States. Overall, we have 
seen changes in the growth of jails in the United States. While we were certainly growing in the number of 
jails as States gained Statehood, there has been a shift in jails structures. The vast majority of jails are small in 
size. There are few larger jails, but they hold more individuals. As can be seen in a report from Cahalan and 
Introduction to the American Criminal Justice System
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