http://www.chesterwalls.info/oldpubs5.html

built in 1810, to designs by Thomas Harrison. It replaced the medieval gateway which at the time contained the city gaol.

http://en.wikipedia.org/wiki/Northgate,_Chester

http://www.matthewpemmott.co.uk/2008/11/chester-city-gates-chester.html

http://www.chestertourist.com/northgate.htm

The medieval gateway and gaol was demolished in 1808

http://www.chestertourist.com/northgate.htm