[3] According to the United States Census Bureau, the township has a total area of 35.2 square miles (91 km2), all land.

13.6% of all households were made up of individuals, and 5.7% had someone living alone who was 65 years of age or older.

None of the families and 0.6% of the population were living below the poverty line, including no under eighteens and 4.4% of those over 64.

Elmer Township is located in Minnesota's 1st congressional district, represented by Mankato educator Tim Walz, a Democrat.

At the state level, Elmer Township is located in Senate District 22, represented by Republican Doug Magnus, and in House District 22A, represented by Republican Joe Schomacker.