[1] Leyden Township is located generally west of the northern part of the city of Chicago, a strip of which (a stretch of land connecting O'Hare International Airport to the main body of the city) bisects the township.

According to the 2021 census gazetteer files, Leyden Township has a total area of 19.92 square miles (51.59 km2), all land.

Leyden also contains Triton Community College located in River Grove.

As of the 2020 census[1] there were 93,096 people, 32,387 households, and 22,127 families residing in the township.

27.60% of all households were made up of individuals, and 11.00% had someone living alone who was 65 years of age or older.