

Ottawa was the site of a famous 1859 extrication of a runaway slave named Jim Gray from a courthouse by prominent civic leaders of the time. Citizens in the city were active within the abolitionist movement. The John Hossack House was a "station" on the Underground Railroad, and Ottawa was a major stop because of its rail, road, and river transportation. Douglas, leader of the Democratic Party, openly accused Abraham Lincoln of forming a secret bipartisan group of Congressmen to bring about the abolition of slavery.

Ottawa was the site of the first of the Lincoln–Douglas debates on August 21, 1858. The North Portage Trail connected the site over land and water to the Chicago River. Here the river was reliably deep enough for canoes. Ottawa occupies a place on the Illinois River that has long been one end of a portage trail between the Mississippi River and Lake Michigan.

It is the principal city of the Ottawa, IL Micropolitan Statistical Area. The population estimate was 18,742, as of 2020. It is located at the confluence of the navigable Fox River and Illinois River, the latter being a conduit for river barges and connects Lake Michigan at Chicago, to the Mississippi River, and North America's 25,000 mile river system. Ottawa is a city in and the county seat of LaSalle County, Illinois, United States.
