This 344 acre Historic District contained thirty-seven contributing buildings and one contributing structure when it was added to the National Register in 1980.

Hercules was a company town owned by the Hercules Powder Works. From 1881 until 1901, it was the largest producer of dynamite in the world.

During World War I, the company became the largest producer of TNT in America. The plant supplied explosives to both sides until America entered the war.

The first plant explosion occurred on January 11, 1882, and was felt nearly 35 miles away. At least six more explosions occurred before 1900. The most disastrous explosion occurred on February 20, 1908. Subsequent explosions were few and confined to small sections of the plant.

On December 15, 1900, the City of Hercules was incorporated, becoming the third incorporated town in Contra Costa County.

Adapted from the NRHP nomination submitted in June of 1980.