According to the United States Census Bureau, the township has a total area of 34.9 square miles (90 km2), all land.

[3] By one account, Adams Township was named by an early settler, William Madden, for a friend of his in New York State.

The first settler, Thomas Knudtson, came in 1855 and built a log house on his claim in Section 2.

12.6% of all households were made up of individuals, and 2.6% had someone living alone who was 65 years of age or older.

Johnsburg is a small unincorporated area near the southern border with Iowa.