At Christ Church in Alexandria, Va., Mary Kimbrough Koontz and Arthur Huntington Nash were married by the Rev. William Sydnor at four-thirty in the afternoon on March 26. A reception was held at the Sulgrave Club in this city.

The bride, daughter of William W. Koontz of Alexandria and the late Mrs. Walter M. Cushman of Charlottesville, was attended by Philippa Lyman Nash of Warrenton as maid of honor; Nancy Harrison James of Lynchburg, Carlyle Fairfax Herbert Hooff of Alexandria, Sarah Thornton Latham of Arlington, Mrs. Alexander Barclay Wharton of Lincroft, N.J.; Sara Jane Sproul of Staunton, and Kay and Susanna Giles of Richmond, the bridesmaids.

The groom, son of James Mallory Nash of Warrenton and Mrs. S. Munson Corbett of Upperville, was served by his father as best man. The groomsmen were: Henry Francis Atherton III, Peter Van Roijen, and Peter Baird Nash, all of Washington; James R. Green Jr. of Markham, Talbot Lackland Talbot of Middleburg, and Christopher Rafferty of Houston, Texas.

Mrs. Nash ws graduated from the Madeira School and in 1972 from Hollins College. Mr. Nash was graduated from Milton Academy (Mass.) and in 1966 from the University of Virginia. He served in the U.S. Marine Corps (1966-1969), and was a helicopter pilot in Vietnam with the rank of Captain. After their wedding trip to Taos, N.M., the couple will live in Warrenton.