State Highway 56 passes through the center of town as Main Street, leading northwest 17 miles (27 km) to Austin, the county seat, and east-southeast 12 miles (19 km) to Le Roy.

The Iowa state line is 5 miles (8 km) south of Adams via local roads.

According to the U.S. Census Bureau, the city of Adams has a total area of 1.00 square mile (2.59 km2), all land.

[1] Unnamed streams pass through the southern and western part of the city, leading west to the Little Cedar River, which flows south to the Cedar River at Nashua, Iowa.

There were 330 housing units at an average density of 326.7 per square mile (126.1/km2).

34.5% of all households were made up of individuals, and 20.4% had someone living alone who was 65 years of age or older.

The racial makeup of the city was 99.25% White, 0.12% Native American, 0.38% Asian, 0.25% from other races.

35.0% of all households were made up of individuals, and 24.9% had someone living alone who was 65 years of age or older.