According to the United States Census Bureau, the township has a total area of 16.9 square miles, of which 16.7 square miles is land and 0.15 square miles, or 0.86%, is water. The city of Ann Arbor was established within the borders of Ann Arbor Township. Over the years, the city expanded, annexing portions of the township as the city grew and reducing the land area of the township. Under a 1994 boundary agreement with the City of Ann Arbor, those areas of the Township lying within the future boundaries of the city will be subject to annexation by the city.

As of the census of 2020, there were 4,747 people in 1,958 households residing in the township. The population density was 288.6 per square mile. There were 2,073 housing units of which 76% are single family dwellings. The racial makeup of the township was 67% White, 1% African American, 0% Native American, 24% Asian, % Pacific Islander, 4% identifying as two or more races. Hispanic or Latino of any race were 4% of the population.  Additional census data for Ann Arbor Township can be viewed

The landscape of Ann Arbor consists of hills and valleys, with the terrain becoming steeper near the Huron River. The elevation ranges from about 750 feet along the Huron River to over 1,000 feet. Ann Arbor is known for its wide variety of trees, foliage, and its lush landscape.

The Township of Ann Arbour  was organized in 1827 by the Legislative Council of the Michigan Territory and the Village of Ann Arbour–which later became the City of Ann Arbor–was organized in 1833. As villages remained part of the township, the Village of Ann Arbour did not become completely detached from the township until it reorganized as the city of Ann Arbor.