HURON - Mary Ellen (Swana) Vaillancourt, 55, died peacefully at home on Sunday, August 9, 2015, after a courageous six and one-half year battle with cancer. Her Mass of Christian of Burial will be at 1:00 pm on Saturday, August 15, 2015 at Holy Trinity Catholic Parish. Cremation will take place after her funeral mass and a private inurnment will be held at a later date. Visitation with the family present will be from 5-7 pm on Friday at Welter Funeral Home; or one hour prior to the service on Saturday. Mary Ellen was born in Webster, Massachusetts on August 25, 1959, the fifth child of Michael R. and Phyllis (Bukowski) Swana. She grew up in Stow, Massachusetts and graduated from Nashoba Regional High School (1977) and North Adams State College (1981) with a B.S. in Biology. She married Dana R. Vaillancourt on August 7, 1982 and the couple had two children, Kelson Michael and Loren Brittaney Vaillancourt. Mary Ellen lived in Stow, Massachusetts; Troy, New York; Augusta, Maine; Belle Fourche, Pierre, and Huron, South Dakota and worked as a medical technologist, environmental educator, biologist, soil conservationist and most recently as a wetland specialist with the USDA Natural Resources Conservation Service. A beloved wife and mother, she was a devout Christian, a 5th degree black belt and gifted teacher in Taekwondo and Tang Soo Do, was involved with the Miss South Dakota Scholarship Program as the director for the Miss South Dakota State Fair pageant for several years, loved art, gardening, camping, kayaking, and playing with her dogs. She leaves her husband, Dana; her daughter, Loren; brothers and sisters; Steven and Margaret Swana of Nashua, N.H.; Michael Swana of Brookfield, Mass.; Susan Swana of Winter Harbor, Maine; David and Tracey Swana of Littleton, Mass; Gary and Judy Vaillancourt of Sutton, Mass.; Guy Vaillancourt of Saco, Maine, and many cousins, nephews and nieces. She was preceded in death by her son Kelson, her parents; sister, Linda (Swana) Allard; father-in-law Francis Vaillancourt, nephews Samuel and Micah Vaillancourt, and sister-in-law, Patricia (Norton) Vaillancourt.