[9] Hecla was the first place to have a soil conservation district in South Dakota.

According to the United States Census Bureau, the city has a total area of 0.34 square miles (0.88 km2), all land.

[10] The Civil Township of Hecla (which includes a portion of South Dakota political township-128-N by range-61-W east of the James River) surrounds the municipal boundary of the City of Hecla.

Liberty Township is located to west of the City of Hecla and includes a portion of South Dakota political township-128-N by range-61-W west of the James River in addition to township-128-N by range-62-W. As of the census[13] of 2010, there were 227 people, 127 households, and 69 families living in the city.

40.2% of all households were made up of individuals, and 22.8% had someone living alone who was 65 years of age or older.

The racial makeup of the city was 99.04% White, 0.32% Native American, and 0.64% from two or more races.

34.0% of all households were made up of individuals, and 19.0% had someone living alone who was 65 years of age or older.