Cooperative Extension Service, in the United States, publicly supported, informal adult education and development organization. Established in 1914 by the Smith-Lever Act, it constitutes one of the largest adult education programs in the world and consists of three levels of organization—federal, state, and county. Its overall objective is to plan, execute, and evaluate learning experiences that will help people acquire the understanding and skills essential for solving farm, home, and community problems. This objective is met through educational programs that make use of research findings emanating primarily from the U.S. Dept. of Agriculture and the state land-grant colleges and universities. The Extension Service also sponsors Four-H Clubs for youth throughout the country.