Mary T. Derosier, 70, of Keene, NH passed away February 24, 2019 in Great Falls, MT. A grave side service will be held at the family plot in the Lower Cemetery in Langdon, NH, where she will be laid to rest with her parents when the weather permits. She was born July 1, 1948 in Keene, NH to Wilfred A. and Theresa D. Derosier. Mary graduated from Vilas High School in Alstead, NH and later attended Elliot Community Hospital School of Nursing in Keene, NH. She married and later divorced Richard A. Briggs of RI. She devoted many years of her life to her work as a Registered Nurse in both RI and NH. Mary is survived by her brother, Wilfred A. Derosier Jr. of TN; sister Ruth Fenton of RI; her children Richard E. Briggs of Langdon, NH and Linda Briggs Sertain of MT, anddaughter MaryLou Sheldon Phaneuf of Keene, NH who was born to Mary and William Oren Sheldon of Walpole, MA; and many grandchildren and great-grandchildren.