The Wausau Paper Mill in Groveton will be closing down at the end of the year, leaving 303 employees out of work.
Company officials made the announcement Tuesday.
Governor John Lynch says the state will do all it can to assist laid off workers and their families.
Androscoggin Valley Economic Development Director Jim Wagner says the paper mill employed many workers who lost jobs when the pulp mill in Berlin shut down.
"One job, ten jobs, or a hundred jobs, it's still devastating. And it's a tremendous impact in the North Country, particularly in the Groveton area. And it's unfortunate but global competition is the playing field these days. And it's really tough to maintain, to sustain viability."
The state's Division of Economic Development is preparing a plan to attract a new company to the site.
Wassau acquired the mill in Groveton in 1993.
