Niagara Mohawk Power Corp., (the “Company”) an indirect subsidiary of National Grid USA (“National Grid”), announced that its Board of Directors has declared dividends for the period April 1, 2012 to June 30, 2012 at the following rates for all outstanding series of its preferred stock: .85% on the $100 par value, 3.40% Series;.90% on the $100 par value, 3.60% Series;.975% on the $100 par value, 3.90% Series. The preferred stock dividends are payable on July 2, 2012, to holders of record on June 18, 2012. The Company, doing business as National Grid, provides electricity service to approximately 1.6 million customers and natural gas service to approximately 565,000 customers in upstate New York. The Company is based in Syracuse, N.Y. National Grid is an indirect subsidiary of National Grid plc (LSE: NG; NYSE:NGG). National Grid delivers electricity to approximately 3.4 million customers in Massachusetts, New Hampshire, New York and Rhode Island, and manages the electricity network on Long Island under an agreement with the Long Island Power Authority (LIPA). It is the largest distributor of natural gas in the northeastern U.S., serving approximately 3.5 million customers in Massachusetts, New Hampshire, New York and Rhode Island. National Grid also owns over 4,000 megawatts of contracted electricity generation that provides power to over one million LIPA customers.