La Salle County is located 60 miles south and west of Chicago. The Illinois River runs through the center and makes it east to west bend and heads south to Peoria. LaSalle county was broken off from Putnam and Tazewell county in 1815. The township make up is typical 6 x 6 (actually 5 x 6) with the exception of the townships where the river runs through and smaller townships make up the north and south side of the river.
The neighbors to LaSalle county are DeKalb to the north, Lee to the northwest, Bureau, Putnam and Marshall to the west, Woodford and Livingston to the south and Grundy and Kendall to the east.
The 35 townships that make up LaSalle county are; Mendota, Meriden, Earl, Adams, Northville, Mission, Serena, Freedom, Ophir, Troy Grove, Dimmick, Waltham, Wallace, Dayton and Rutland, Miller, Manlius, Fall River, Ottawa and South Ottawa, Utica and Deer Park, LaSalle and Peru, Eden Vermillion, Farm Ridge, Grand Rapids, Brookfield, Allen, Otter Creek, Bruce and Eagle, Richland, Hope, Osage and Groveland.