The 1862 Morrill Act gave the land grant colleges their mandate to teach. The colleges acquired a research function in 1887 through the Hatch Act, which recognized the need for original research to underpin the teaching of agriculture and help develop agricultural innovations. The legislation funded a system of state agricultural experiment stations (SAESs), most of which were established under the direction of the 1862 land grant colleges. Table 1-2 outlines a chronological progression of legislation mandating the many iterations of the land grant college system.

Today SAESs operate in conjunction with and, in almost all cases, on locations at colleges of agriculture. Connecticut and New York, in addition to on-campus SAESs, have an off-campus SAES. Many other states have branch stations, that is, SAES subsidiaries located off campus and often in agricultural areas of direct interest to the branch station's research.

Most faculty at land grant colleges of agriculture have SAES appointments. This grants them potential access to "Hatch" research funds, which are administered by USDA and funneled to the SAESs on a formula basis. Some faculty scientists who have SAES appointments also conduct research at other colleges that have related programs, such as in the life sciences. The SAES director and the dean of the college of agriculture are usually, but not always, the same person.

With the 1914 Smith-Lever Act, the colleges took on a third function, called "extension," which was designed to disseminate agricultural college-generated knowledge beyond the campus to farms and consumers. Extension was to be a cooperative activity between the federal government (through USDA) and the states (through the land grant colleges). County governments, through a network of county extension agents, soon became cooperative extension partners.