 Bertrand Township was established in 1836, and named for Joseph Bertrand, a pioneer citizen.According to the United States Census Bureau, the township has a total area of , of which is land and , or 1.71%, is water.The township is in the southeast portion of the county, with Galien Township to the west, Weesaw Township to the northwest, and Buchanan Township with the village of Buchanan to the north on the west side of the township.