Fitchburg Gas and Electric Light Company (FG&E), a Massachusetts corporation organized in 1852, became part of the Unitil system in 1992. FG&E originally manufactured gas to illuminate the gas lights in downtown Fitchburg. Today, FG&E provides retail electric and natural gas distribution service in a 170-square-mile service area in north-central Massachusetts, with an estimated population of 82,000. This includes electric distribution service to 25,000 customers in the communities of Fitchburg, Townsend, Lunenburg and Ashby, and natural gas distribution service to 15,000 customers in the communities of Fitchburg, Townsend, Lunenburg, Ashby, Westminster and Gardner.

Granite State Gas Transmission was incorporated in New Hampshire in 1955 and became part of the Unitil system in 2008. Granite’s principal business is delivering natural gas transportation services to Northern Utilities and providing access to inter-state natural gas pipeline supplies over 87 miles of FERC-regulated pipeline located primarily in Maine and New Hampshire.

Northern Utilities was incorporated in New Hampshire in 1979 and became part of the Unitil system in 2008. Northern’s predecessor companies date back over 150 years to the Portland Gas Light Company formed in 1849. Northern Utilities is a local natural gas distribution utility serving 52,000 customers in 44 communities in the Seacoast Region of New Hampshire and Southern Maine. This includes in New Hampshire: Atkinson, Dover, Durham, East Kingston, Exeter, Greenland, Hampton, Hampton Falls, Kensington, Madbury, Newington, North Hampton, Pelham, Plaistow, Portsmouth, Rochester, Rollinsford, Salem, Seabrook, Somersworth and Stratham. And in Maine: Auburn, Biddeford, Cape Elizabeth, Cumberland, Eliot, Gorham, Kennebunk, Kittery, Lewiston, Lisbon, Lisbon Falls, New Gloucester, North Berwick, Old Orchard Beach, Portland, Saco, Sanford, Scarborough, South Berwick, Wells, Westbrook and York.

Unitil Energy Systems (UES) is a New Hampshire corporation, the successor company from the 2005 combination of Concord Electric Company and Exeter & Hampton Electric Company. Concord Electric Company was organized in 1901 to provide electric service to customers in Concord, NH. Exeter & Hampton Electric Company was organized in 1908 to provide electric services to customers in Exeter, Hampton and surrounding communities. Today, UES provides electric distribution service to more than 72,000 customers in the Capital and Seacoast regions of New Hampshire, serving the 31 communities of Allenstown, Atkinson, Boscawen, Bow, Brentwood, Canterbury, Chichester, Concord, Danville, Derry, Dunbarton, East Kingston, Epsom, Exeter, Greenland, Hampstead, Hampton, Hampton Falls, Hopkinton, Kensington, Kingston, Loudon, Newton, North Hampton, Pembroke, Plaistow, Salisbury, Seabrook, South Hampton, Stratham, and Webster.

Unitil Resources, Inc. was incorporated in New Hampshire in 1993 as a non-utility subsidiary of Unitil. Its subsidiary, Usource LLC., provides energy brokerage service to large energy users throughout the Northeast seeking competitive electricity or natural gas supplies.

Unitil Service Corp. was incorporated in 1984 to provide centralized administrative and management services to Unitil System subsidiaries. Unitil Service Corp. is located at Unitil's corporate headquarters facility in Hampton, New Hampshire, and operates a customer service center in Concord, New Hampshire.