It is north of Canton, west of Peoria, southeast of Galesburg, and northeast of Macomb.

[5] Before and during the Civil War, the city was involved in the Underground Railroad, and there are several remaining homes that were safehouses.

Farmington is located in the northeast corner of Fulton County.

IL 116 enters from the north as North Main Street, and IL 78 enters from the south as South Main Street.

According to the 2021 census gazetteer files, Farmington has a total area of 1.51 square miles (3.91 km2), all land.

32.41% of all households were made up of individuals, and 14.03% had someone living alone who was 65 years of age or older.