[4] Interstate 35 and Carlton County Road 61 are two of the main routes in the township.

According to the United States Census Bureau, the township has a total area of 39.9 mi2 (103.3 km2), of which 39.7 mi2 (102.7 km2) is land and 0.2 mi2 (0.6 km2) (0.63%) is water.

The Saint Louis River flows through at the western edge of Thomson Township.

The Midway River and Crystal Creek both flow through Thomson Township.

15.1% of all households were made up of individuals, and 5.6% had someone living alone who was 65 years of age or older.