DOVER, N.H. — A 143-year-old family owned New Hampshire newspaper will be sold to a neighboring newspaper group by the end of the year.

Patty Foster, president and publisher of Foster’s Daily Democrat in Dover, announced the paper’s sale to Portsmouth-based Seacoast Media Group in a letter to employees Wednesday.

The assets of Geo. J. Foster & Co., Inc., and Eastern Marketing Services will be sold to the publisher of the Portsmouth Herald, The Exeter Newsletter, and the York County Coast Star. Seacoast is a subsidiary of New Media Investment Group Inc.

The letter says Seacoast “will continue to publish under the Foster’s Daily Democrat banner, hopefully for a long time.”

Foster said the sale offers “a solid and sure way forward.” She said everyone will be offered a position.