Department of Agriculture, executive department of the United States government that carries out programs of research, education, conservation, forestry, marketing, credit, export expansion, food distribution, production adjustment, grading and inspection, and development of rural areas. The department was first established about 1836 as a branch of the Office of the Commissioner of Patents, with the purpose of distributing plants and seeds to farmers. It was established as a department of agriculture by Congress in 1862 and raised to cabinet level in 1889. It is administered by a secretary appointed by the president with the approval of the Senate.

About the time the department was raised to cabinet level, the reserves of public lands available for homesteading were becoming depleted. Instead of moving from worn-out land to free or less expensive fertile lands, farmers had to seek the aid of scientific techniques to increase production and income. Consequently, from about 1890 on, the responsibilities of the department grew rapidly. Existing units of the organization were merged and new units were created to carry on research and service activities and to administer regulatory laws.

The growth and expansion of the Department of Agriculture continued during the depression of the 1930s, when the problem of surplus farm products became extremely acute. The department was reorganized several times. During World War II (1939-1945), many bureaus were split off to establish the War Food Administration, but these bureaus were returned to the unified control of the department in a reorganization begun just after the war.

The following are among the major units of the Department of Agriculture. The Cooperative State Research Service and the Agricultural Research Service work with state agencies to improve the effectiveness of research in such areas as human nutrition, soil and water conservation, processing and distribution of farm products, and climatic environmental conditions. The Food and Nutrition Service administers food assistance programs, including food stamp, school breakfast and lunch, special milk, and summer food service programs.

The Agricultural Marketing Service assures safe, efficient movement of products from producer to consumer. The Animal and Plant Health Inspection Service safeguards the health and quality of animals and plants and protects the consumer by means of federal and state meat and poultry inspection. The Food Safety agency provides for federal inspection of poultry, meat, and related products to be sure they are labeled honestly and informatively and that they are safe and wholesome. The Federal Grain Inspection Service sets standards and regulates the inspection and weighing of all types of grain.

The Economics Research Service publishes information that helps officials to develop and administer agricultural policies and programs. The National Agricultural Statistics Service prepares estimates of production, price, and supply figures concerning agricultural commodities. The Foreign Agricultural Service works to develop markets abroad and expand agricultural exports. Under its sponsorship, technicians work in developing nations to improve agriculture and officials of developing nations receive agricultural training in the United States. Other units of the Department of Agriculture include the Commodity Credit Corporation, the Agricultural Cooperative Service, the Extension Service, the Federal Crop Insurance Corporation, the Forest Service, the Rural Housing Service, and the Rural Utilities Service.