Built 1888 to 1890, the Electric Building (later called the Electric Block) had coal-fired steam dynamos in the basement that generated much of Helena's electricity until 1898, when hydroelectric power from the first Canyon Ferry Dam came online. The building also housed businesses, offices and apartments. In 1891, the Montana Senate met there.

The disused 120-foot tall stone and brick chimney was removed in 1905, accompanied by extensive renovations. In 1910, an additional story was added, along with more renovations, including the installation of an automatic elevator, the first of its kind in Helena. In 1911, the Helena YWCA was first organized in one room of the Electric Block.

Helena Baby Boomers may recall having their photos taken at the Swenson-James Studio.

On January 7, 1974 the City Commission awarded a contract for demolition of the Electric
Block and the Electric Block annex to the Norman Rogers Mining Co. of Helena for $57,800. Rogers was the low bidder.

In 1977, a parking garage was built on the site. Contractors ran into problems while setting footings for the garage, encountering stubborn sub-basements and mining tunnels.