Washington-St. Tammany Electric Cooperative, Inc. received its charter from the State of Louisiana to operate as a non-profit corporation on February 4, 1938. The name of this new corporation was Washington - St. Tammany Electric Membership Corporation. On October 25, 1940 the corporation was converted to a cooperative and changed its name to Washington St. Tammany Electric Cooperative, Inc.

In 1938, WSTE opened its first office and began its commitment to the service of its members in its service area covering the parishes of Washington, St. Tammany, and Tangipahoa in a building on Washington Street owned by Maurice Magee Furniture Store. The Cooperative has operated out of offices in the Waverley Rock House on Cleveland Street, the Warren Gas Building on 11th Avenue, the Prentiss Magee building on Main Street and since 1948 at the present location located on the corner of Pearl and Lee Streets.

WSTE presently has three branch offices, all located in St. Tammany Parish. Locations are, Folsom Branch Office on Highway 40 in Folsom, Abita Springs Branch Office on Mire Drive in Abita Springs and Slidell Branch Office on Gause Boulevard in Slidell.

WSTE's first branch office opened in 1960 in Slidell and was located in a rented building on Highway 190 near the present North Side Shopping Center. In May 1960, WSTE purchased a house and property located in the Log Cabin Subdivision on Gause Boulevard. The property was large enough to house a pole yard and Branch Office operated out of the office building. The Slidell Branch Office operated out of these facilities until September 1979. In September 1979, the present office building on Gause Boulevard in Pearl Acres Subdivision was dedicated. The new property on Gause Boulevard contained 6 acres that now houses the Slidell Branch Office Building, pole and equipment yards and the Pearl Acres Substation.

In March 1974, WSTE purchased a site on Mire Drive near the Town of Abita Springs for the establishment of a branch office with a pole and storage yard. This office was opened to serve the members of this area in the summer of 1974.

In January 1979, WSTE purchased a site on Highway 40 in the Village of Folsom for the establishment of branch office. This office was opened to serve the members of this area in April 1979.

WST Electric Cooperative, Inc. serves the areas of Washington, St. Tammany and Tangipahoa Parishes and the southern part of Marion County in Mississippi. The Cooperative has grown from an organization of 2 employees and no members and no electric lines to the present organization of 128 employees that serves over 50,000 accounts, has 183 miles of transmission lines, over 4905 miles of distribution lines, 7 transmission substations, 2 transmission switching stations and 30 distribution substations.

Washington-St. Tammany Electric Cooperative, Inc.'s main goal and objective since the establishment of the Cooperative is to provide its members with the best service at the lowest available cost.