LaSalle County is located within the Fox Valley and Illinois River Valley regions of the U.S. state of Illinois. As of the 2020 Census, it had a population of 109,658. Its county seat and largest city is Ottawa. LaSalle County is part of the Ottawa, IL Micropolitan Statistical Area of Northern Illinois.

North Utica, often known as Utica, is a village in Utica Township, LaSalle County, Illinois. The population was 1,323 at the 2020 census. It is part of the Ottawa Micropolitan Statistical Area.