Northfield Township is a civil township of Washtenaw County in the U.S. state of Michigan. The population was 8,514 at the 2020 census.

Washtenaw County is a county located in the U.S. state of Michigan. At the 2020 census, the population was 372,258. The county seat and largest city is Ann Arbor. The county was authorized by legislation in 1822 and organized as a county in 1826. Washtenaw County comprises the Ann Arbor Metropolitan Statistical Area. The county is home to the University of Michigan, Eastern Michigan University, Washtenaw Community College, and Concordia University Ann Arbor.