LaSalle County is located in the state of Illinois and comprises a total area of 1,144 square miles. The official county seat is Ottawa, which serves as the county's largest city, though other municipalities in the county include Streator, Oglesby, and Peru. The county is part of the Ottawa-Peru, IL, Metropolitan Statistical Area. The county was founded in 1831.

LaSalle county is governed by a nine-member County Board of Commissioners. The LaSalle County government is responsible for maintaining roads and public infrastructure, enforcing laws, distributing tax revenue to local governments, recording documents and property transactions, maintaining public health, and more. LaSalle County also participates in local, state and federal election processes, and provides a range of resources and services to its residents.

For the most up-to-date and in-depth information, please check the public records links below.