Miriam C. O'Brien, of Concord, died Tuesday, June 23, 2020, at the University of Massachusetts Medical Center in Worcester. She was ninety–five. Born in Waltham on September 10, 1924, she was the daughter of the late James F. Cary of New Richmond, Michigan, and Emma M. Travis of Weston. Following the death of her father in 1935, she moved to her mother's family home in Weston, graduating with the Weston High School Class of 1942. Beginning a lifelong career in health services after graduation, she earned a diploma as an attendant nurse from the New England Peabody Home for Crippled Children in Wellesley in October 1943. From October 1944 to October 1945, she belonged to the WAVES, serving in the U.S. Navy Hospital Corps, and was honorably discharged as a Pharmacist's Mate, Third Class. During her tour in the Navy, she trained and served at Hunter College in New York City, Bethesda Naval Hospital in Washington, D.C., and Great Lakes Naval Training Station in Chicago. While in service, she returned to the area to marry John S. O'Brien of Concord on June 3, 1945. ("Jack" O'Brien was born in Concord in 1917, was a driver for Greyhound Lines from 1943 to 1971, and died in 1975). Following World War II, Jack and Mim lived in Weston. Mim was an attendant at Weston Manor nursing home, and was a visiting nurse for Weston physician Dr. David Reid. She and Jack moved to Concord in 1958 and bought a tract house newly–built in a vacant field at the end of Elsinore Street known as "The Fairgrounds." Mim lived there until her death. In her early years in Concord, Mim worked as a saleswoman at The Country Store and as a hostess at The Colonial Inn. She returned to medicine around 1965, becoming the secretary of Concord physician Dr. Earl Bracker and, later, of Dr. Bracker and Dr. Sidney Wanzer in a group practice. Afterward, she became a medical secretary in the office of Concord dermatologist Dr. Samuel Goos. She became a certified EMT in her early sixties and finally worked in the Cardiology Department at Emerson Hospital, before retiring at the age of eighty. Mim's two greatest loves were community theater and choral music. After returning from the service, she appeared on stage in productions by The Hovey Players of Waltham, The First Parish Friendly Society of Weston, Vokes Theater of Wayland, and The Concord Players. In the 1950's, she sang with an amateur group of Weston women called "The Kitchen Canaries." She sang regularly with The Concord Chorus from 1965 to 2002. In the 1980's, she and her close friend Carole A. Riordan sang with the American Union of Swedish Singers, and they toured Sweden with the group in 1989. In her later years, when she was too old to participate actively in public performances, she served as a volunteer with Open Table of Concord. Throughout her life, she was a member of the Upham Family Society of Melrose. She is survived by her son, James F. O'Brien, and his wife Katherine ("Kathy"), of Port Saint Lucie, Florida, and by her son, Neal D. O'Brien, of Concord. She is also survived by her cousins, Barbara House of Falling Waters, West Virginia, Jean Mickle of Concord, and Carolyn Puffer of Newmarket, New Hampshire, as well as many colleagues and friends. Burial at Sleepy Hollow Cemetery in Concord will be private. A memorial service will be held at a later date. Arrangements are under the care of Dee Funeral Home & Cremation Service of Concord.