The Gasholder House, the one-of-a-kind Concord Gas Light Company structure, was named to the National Register of Historic Places.
The 130-year-old red-brick coal gasholder building in Concord's South End is believed to be the last of its type in the country.
The round building with a cupola atop its conical roof was built in Concord in 1888 when coal gas was a major source of light and heat. It was last used in 1953, but its original equipment remains.
The New Hampshire Division of Historical Resources announced the listing Monday.
The gasholder worked this way: Coal gas was pumped into a wrought-iron, 120,000 cubic foot tank that floated atop water. The tank rose and fell based on how much gas was present. The tank's weight provided constant pressure to force the gas out through pipes, where it was distributed to the public.
The city of Concord sponsored the nomination for the historic honor and preservation. Concerns were raised after a tree fell on the structure during a storm, piercing the north roof slope.
The building was temporarily stabilized, but not repaired.
Listing to the National Register does not impose new restrictions or limitations on the use of private or non-federal properties.
In New Hampshire, the listing makes applicable property owners eligible for grants, such as the Land and Community Heritage Investment Program, LCHIP.