The cooperative colony managed by Three Arrows Cooperative Society, Inc. originated with the purchase of Barger Farm, a hilly 125-acre property in Putnam Valley, NY in December 1936. The original organizers, among whom were Louis Hay, a psychologist, Joseph Glass, an attorney, and Jack Schaffer, a member of the Socialist Party familiar with the local area, obtained a state charter as the Barger Street Cooperative Society in 1937 and began to sell shares in the venture for $100, with a minimum purchase of two shares. By the end of the second season thirty families had purchased shares, and a number of tents had been erected on the property. Many of the first participants were affiliated with the International Ladies Garment Workers Union, the Amalgamated Clothing Workers of America, the Jewish Labor Bund, the Socialist Party, USA, or the Party's youth group, the Young People's Socialist League. Some had attended socialist summer camps as children. The colony later adopted the name Three Arrows Cooperative Society to honor a traditional symbol of the international socialist movement. An important influence on the early members was long-time Socialist Party leader, Norman Thomas, who visited Three Arrows every summer and spoke there during his several presidential campaigns. After his death in 1968, the colony's social hall was named for him.

The Society's land is held in common, but individual families own the residences they occupy, and a few units are available for rental. By 1947 the colony, sometimes known as Camp Three Arrows, consisted of fifty-three bungalows. The seventy-fifth, and final, unit was purchased in 1973. In the first few years residents dined communally, but later individual cabins had their own kitchens. Residences have been renovated and expanded to varying degrees and in different styles, with a number of families winterizing their properties for year-round use. Important community decisions at Three Arrows are made through a process of direct democracy. Management is in the hands of a Board of Directors, and a multitude of committees addresses specific areas of responsibility. Paid staff are the full-time caretaker and professional lifeguards, but community members often join in on maintenance projects. By the 1990s the community had become Putnam Valley's largest tax-payer. In the face of soaring land values and the tendency of children and grandchildren of society members to move away from New York and give up ownership of family properties, the community works hard to screen prospective buyers and maintain the cooperative values that motivated the founders.

The colony offers a lively schedule of summer cultural activity, including art classes, Friday-night lectures on political and social welfare topics, discussion sessions known as "schmoozes," concerts, amateur theatricals and dances. There are two clay tennis courts, a ball field and a marked trail for hiking. The community hosts a gala Fourth of July picnic, to which many non-residents are invited, and there is an annual Labor Day show. A waterfront swimming and boating area on fifty-acre Barger Pond, includes enclosed swimming "cribs" and a floating deck for lounging and socializing, and a number of supervised activities for children have been developed over the years.