Cynthia Ellen Elizabeth Virginia Addington was born in Coeburn, Wise County, Virginia, on December 12, 1898. Her father, James L. ("Dot") Addington, owned a "racket," or mercantile, store in town. Cynthia attended Virginia Intermont College in Bristol and graduated in 1918 with a teacher's degree in voice, harmony, and history of music. She married Roy Gilley Boatwright in 1919 and gave birth to their only child, a daughter, Ida Virginia Frances, in 1921. Her husband worked as a cashier at the First National Bank and then at Cynthia's father's store. From 1943 to 1965, he was the Coeburn Postmaster.

Soon after her marriage, Boatwright turned her energies toward volunteer work, a passion that proved consistent throughout her life. In the 1920s and 1930s, she was active in such local clubs and groups as the Methodist Missionary Club, the Woman's Society of Christian Service, and the Coeburn Women's Club. As chair of the Christian Social Relations Committee and Local Work, she taught Bible Class at the Colored Church every second Sunday. She was involved in the Children's Home Society and served on the executive committees of the Virginia Cancer Foundation and chapel fund of the Industrial Farm for Women. She served on the advisory council of the Virginia League for Planned Parenthood.

But Boatwright's activities were not just limited to club work. She was the first woman in Wise County to run for public office and served on the Coeburn Town Council from 1934 to 1938.

Beginning in the late 1930s, Boatwright became increasingly involved in the Virginia Federation of Women's Clubs (VFWC). She was President of her local district women's club from 1935 to 1938, and in 1938, she was elected Vice-President of the VFWC. The pinnacle of her VFWC career was as President in the war years of 1941 to 1944. She was the first southwest Virginia woman to be President of that organization. During her years as President, the VFWC turned its attention to the war effort, by donating ambulances to the Red Cross, encouraging women to volunteer for civil defense, conservation, and nursing services, and supporting the USO. Her theme was "Let us rise up and build."

Other activities of the 1940s included being appointed in 1941 by Governor James H. Price to the State Defense Council and serving from 1944 to 1947 as chair of the General Federation of Women's Clubs Aviation Defense Board. Boatwright was president of the Coeburn Woman's Club from 1945 to 1946 and President of the Wise County Federation of Women's Clubs from 1944 to 1947.

Although she was born a Baptist, Boatwright became a Methodist after her marriage, and she actively applied her energies to the church all her life. She played the piano for Sunday church and funeral services throughout her lifetime. From 1947 to 1951, she served as President of the Big Stone Gap district of the Women's Society of Christian Service. In 1960, she headed a fund drive for additions to buildings at the district Methodist Camp.

When Virginia Polytechnic Institute merged with Radford College in 1944, the composition of the Board of Visitors changed from fifteen to sixteen members, with four of these to be women. Boatwright was appointed in December 1944 as one of these first four women on the VPI-Radford College Board of Visitors, where she served until 1953.

Boatwright worked strenuously for the Democratic Party in the late 1940s and 1950s. She was a member of the Democratic State Central Committee and chair of the Virginia Ninth District Democratic Party Women's Division, and delegate to the 1952 and 1956 National Democratic Conventions. From 1954 to 1958, she was the Virginia representative to the National Democratic Advisory Committee on Political Organization.

Other organizations in which Boatwright was involved include the Virginia Heart Fund, the Virginia Cancer Foundation, Breaks of the Cumberland Park, and the Eastern Wise Chapter of the American Red Cross. She also wrote about Coeburn social and community events for the Coalfield Progress.

Boatwright died on March 5, 1973, in Grundy, Virginia. She is buried in the Laurel Grove Cemetery in Norton, Virginia.