Surrey County Gaol (Leigh Hunt's place of imprisonment from 1813 to 1815), also known as Horsemonger Lane, is located at G-10 of David Perdue's wonderfully clear, color-coded map.

Compliments of archivemaps.com (copyright MAPCO), a map of London (Surry area) in 1800:

GREENWOOD'S MAP OF 1827 (Horsemonger Lane is at the bottom right corner)