Camp Mystic was established in 1926 by The University of Texas coach “Doc” Stewart.  Camp Mystic had one eight-week session from the beginning until 1942.  After World War II Camp Mystic began offering two sessions, and later added a two week third session in 1983.

Agnes Stacy, fondly called "Ag," became familiar with Camp Mystic in 1933 when she sent her daughter Anne to Mystic. The next year, Ag attended Mystic herself as a director. In 1939, she and her husband, "Pop" Stacy (shown right), decided to purchase the camp. They began many of the traditions which are still followed by Mystic's campers.

Ag, shown at right with her husband and two children, Anne Stacy Eastland Spears and William Gillespie Stacy Jr.,  kept Mystic in continuous operation, except for the years 1943-45, when it was leased by the federal government as a rehabilitation and recovery camp for army air corps veterans of World War II.

Mr. and Mrs. Frank C. Harrison, affectionately called "Iney and Frank," were brought to Mystic in December of 1948 by Ag. Before coming to Mystic, Iney was a teacher for many years, and then worked alongside her husband, Frank, in Baytown.  They were directors of Mystic from 1948 until their retirement in 1987.  Both influenced the lives of countless young women and men by their example and through their training. Both are credited with putting into practice many of the philosophies and traditions still valued by Mystic campers and counselors.