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Mary Jo Detweiler

Mary Jo Detweiler, the first female library director in Prince William County, led the system from 1975 to 1985.

Mary Jo Detweiler (née Holmes), librarian, Christian educator, and beloved and adoring mother and grandmother, died peacefully of natural causes on February 25, 2022.

Born in Indianapolis to Burnham Holmes and Josephine Seymour Holmes, she attended the University of Michigan (B.A., Phi Beta Kappa) and Indiana University (M.A., library science).

Mary Jo met her future husband, the Rev. William R. Detweiler, working at Waycross Episcopal summer camp in Indiana. She and Bill celebrated 50 years of loving marriage in 2013.

After the birth of their children, the family moved to Manassas, Virginia, in 1975, for Mary Jo to serve as director of the Prince William County Library System. Upon her departure in May, 1985, The Potomac News editorialized, “Next week, Mrs. Detweiler will leave her post, and she will be missed. Hers was a voice of [library] advocacy combined with reason, of concern for people combined with professional skill. There could be no finer leader for the system.”

Later in her career, Mary Jo worked with library computer systems, provided library staffing services, taught library science classes at Catholic University and George Mason University, and served as a librarian at Virginia Theological Seminary. She also immersed herself in information as a guide for the Catechesis of the Good Shepherd, a religious education program for small children.

Mary Jo is survived by her siblings Sally Nelson and Dwight Holmes and their spouses Pete Nelson and Michelle Burns; her daughter Elizabeth Detweiler and son Hans Detweiler and their spouses Guillermo Canizales and Julieanne Ehre; grandchildren Anna Canizales, Pablo Canizales, Esther Detweiler, and Avi Detweiler. She is predeceased by her husband and her brother, Douglas Holmes.

Contributions in Mary Jo’s memory may be made to St. Mark’s Episcopal Church in D.C. or the Chesapeake Bay Foundation. Remembrances will be shared Saturday, May 7, at 4 p.m., at River Towers, Alexandria, Va.

Potomac Local News publishes obituaries submitted by established funeral homes.

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