East of Airport Road and north of Hwy 9, Adjala-Tosorontio Township is located in the south western part of Simcoe County. It is 372.38 square kilometers and has a population of approximately 10,603 people.

The area features rolling countryside and is a predominantly rural area with the Nottawasaga River cutting through it. There are many small villages and hamlets including Achill, Airlie, Athlone, Ballycroy, Cedarville, Colgan, Connor, Everett, Glencairn, Hockley, Keenansville, Lisle, Loretto, Rosemont, Sheldon, Tioga and Tuam.

"Tosorontio" is a Huron word meaning "Beautiful Mountain", and Adjala was the name of the wife of Chief Tecumseh, for whom the neighbouring township (now called New Tecumseth) was named.