what county is trenton, il in?
Trenton, Illinois. Trenton is a city in Clinton County, Illinois, United States. The population was 3,184 at the 2010 census.
Sponsored Topics. Trenton is a city in Clinton County, Illinois, United States. The population was 2,610 at the 2000 census. Trenton is located at 38Â°36â²21â³N 89Â°40â²54â³W / 38.60583Â°N 89.68167Â°W / 38.60583; -89.68167 (38.605943, -89.681725). According to the United States Census Bureau, the city has a total area of 1.0 square miles (2.5 kmÂ²), all of it land.