In 1952 the 4-H Valley Riders was established to serve teenagers who loved horses. In 1959 as an outgrowth of this club, the Southern Marin Horsemen’s Association was formed to continue the guidance and instruction to the juniors, but also to provide an opportunity for adults to join and be active in one of the most rewarding recreational activities. Its constitution called for three classes of members: Senior members, Junior members 18 years old and younger, and Non-Horse Owners. Any person or family member owning at least one saddle- or driving-horse was eligible. The association met the first Friday of each month at the Edna McGuire School at 8:00 p.m. These meetings included movies on horses, instruction in care, shoeing, and feeding. Presenters were people who were experts in these fields. Members erected a riding ring on the corner of East Blithedale and Camino Alto. There were annual horse shows, the first one in 1959. By 1971 there were 166 members who participated in such events as trail rides and tests, schooling, Gymkanas, tack swaps, training as well as social get togethers. One objective was to establish and maintain well-marked hiking and riding trails in the open space lands around Mill Valley. By May 31, 1980, the organization was defunct.