Franklin Township is a civil township of Lenawee County in the U.S. state of Michigan. The population was 2,939 at the 2000 census.
According to the United States Census Bureau, the township has a total area of 39.3 square miles (101.8 km²), of which 38.5 square miles (99.7 km²) is land and 0.8 square mile (2.1 km²) (2.11%) is water.
As of the census of 2000, there were 2,939 people, 1,071 households, and 846 families residing in the township. The population density was 76.4 per square mile (29.5/km²). There were 1,275 housing units at an average density of 33.1 per square mile (12.8/km²). The racial makeup of the township was 98.03% White, 0.07% African American, 0.10% Native American, 0.31% Asian, 0.48% from other races, and 1.02% from two or more races. Hispanic or Latino of any race were 1.09% of the population.
There were 1,071 households out of which 36.4% had children under the age of 18 living with them, 68.3% were married couples living together, 7.1% had a female householder with no husband present, and 21.0% were non-families. 17.1% of all households were made up of individuals and 5.5% had someone living alone who was 65 years of age or older. The average household size was 2.74 and the average family size was 3.08.
In the township the population was spread out with 27.2% under the age of 18, 6.2% from 18 to 24, 30.4% from 25 to 44, 26.9% from 45 to 64, and 9.4% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 102.0 males. For every 100 females age 18 and over, there were 102.5 males.
The median income for a household in the township was $56,296, and the median income for a family was $61,979. Males had a median income of $47,083 versus $25,691 for females. The per capita income for the township was $24,300. About 1.6% of families and 2.7% of the population were below the poverty line, including 1.7% of those under age 18 and 3.0% of those age 65 or over.