May Ellingsen was born on March 13, 1914 to George and Robina Freeman. Her maternal grandfather, Michael Manson, was the first person to pre-empt land on Cortes Island, claiming a quarter section on Gunflint Lake in 1886. May spent her childhood on Hernando Island, where her family homesteaded and logged, and on Cortes Island, where she attended the log school at Manson's Landing.
In 1936 May married Elmer Ellingsen. They spent the next ten years in the Loughborough Inlet/Phillips Arm area while Elmer worked for his father's logging operations. During those years their children, Shirley, Bruce and Andy, were born. In 1946 the family moved to Von Donop Creek, where Elmer was logging. In 1950 they moved their float house, built at the time of their marriage, to Manson's Landing Lagoon and two years later, to its present permanent location on Hague Lake.
May and Elmer devoted much time and energy to building their community. Amongst her many community activities, May ran the library at Manson's Hall. She had a strong interest in local history, researching the history of land pre-emptions on the island, collecting and annotating photographs from pioneer families and recording interviews with old timers. She was a founder of the Cortes Island Museum and Archives Society; the archives reading room is named in her honor. Historical materials and artifacts gathered by May formed the kernel of the museum's collections and archives.