Subgroup 1, Series I consists of annual reports from extension agents assigned to specific programmatic areas and date from 1911 to 1973. Series II includes annual reports from county extension offices in Oregon from 1914 to 1998. Very few county annual reports were generated after 1980. The remaining series are reports of 4-H activities or of special projects and programs.

Because of the manner in which some of the records were microfilmed, titles for series I through III differ in Subgroup 2 (Director's Office) between the microfilmed records and those in paper format. The microfilm records in Subgroup 2 comprise three series. Series I includes correspondence pertaining to teaching administrative matters, events and projects from 1958 to 1968. Series II consists of extension agents' field reports from 1966-67. Series III. is the History of the Cooperative Extension Service in Oregon, 1911-1961, by Frank L. Ballard.

In Subgroup 2, Series I pertains to the general administration of the Extension Service in Oregon, including administrative policies and procedures, civil rights compliance, history of the Extension Service, and personnel issues. The records date from 1911-2002. Series II documents the Extension Service's relationship with local, state and federal agencies and other organizations between 1903 and 1997, particularly the National Association of State Universities and Land-Grant Colleges. Series III documents the relationship between county extension offices and the extension administration at Oregon State. Series IV includes records of economic development related programs from the 1960s and 1970s. Series V documents special events and activities, such as annual staff conferences and Urban-Rural Conferences. Series VI documents the funding and budgeting of the Extension Service at both the state and federal levels. Series VII documents the impact of federal higher education legislation on the Extension Service. Series VIII pertains to office space in county offices and on campus. Series IX documents the development of various Extension Service programs, including the county economic conferences held every decade from the 1920s to the 1970s. The series also contains records pertaining to the Extension Service's long-range planning efforts. Series X includes records of projects participated in by extension agents between 1914 and 1988. Particularly well documented are projects pertaining to marketing and the U.S. Agency for International Development (USAID).

Series XI includes records pertaining to promotion of the Extension Service and agreements with other entities such as the U.S. Soil Conservation Service. Series XII includes records pertaining to publications of the Extension Service and the U.S.D.A., and speeches and articles by extension administrators and other OSU faculty. Series XIII and XIV include recurring and routine reports, project plans of work and reports, annual and biennial reports for the Extension Service, and special reports. Series XV documents the professional development of extension service personnel as well as short course offered in the 1960s and 1970s. Series XVI contains theses and dissertations completed by extension agents as part of their graduate training while employed by the Extension Service. Series XVII contains farmhouse plans from the 1930s through the 1950s and plans and drawings pertaining to county and administrative office space. Series XVIII includes oversize materials from other series, such as maps, posters, and scrapbooks. Series XIX contains correspondence, meeting minutes, reports and general information of a commission created in 1975 by the Oregon Legislature and the State Board of Higher Education to evaluate the OSU Extension Service. Series XX contains files of major programs from the late 1970s through the mid-1990s.

Subgroup 3, Home Economics Extension (microfilm only), includes two series: county demonstration agent reports and state leader annual reports, written between 1915 and 1969.

Subgroup 4, 4-H & Youth Program , contains seven series: I. Administration; II. Program Development; III. Associations, Agencies and Organizations; IV. Events and Activities; V. Awards; VI. Reports; and VII. Sound Recordings. Series I contains materials pertaining to the history of 4-H in Oregon, policies, committees and task forces, and the Oregon 4-H Foundation. Series II consists of plans of work and program reviews. Series III contains records of 4-H related organizations, such as the Oregon 4-H Leaders Association and Mu Beta Beta (4-H honorary society). Series IV documents 4-H events and activities, such as the national 4-H congresses and conferences, the International Farm Youth Exchange Program, and the 4-H summer school. Series V consists of records of 4-H awards and scholarship winners on the national and state levels. Series VI contains annual, statistical, enrollment and special reports. Series VII contains recordings of musical performances given by 4-H members and discussions on various topics by 4-H members and leaders.

Subgroup 5, Extension Council (microfilm only) contains records of a board consisting of Dean of the School of Agriculture, the Director of Extension, and 24 others who were either School of Agriculture department heads or Extension staff. This board at one time set policy for Extension work in Oregon. These records were originally a separate record group.

Subgroup 6, Records from Counties, consists of county level programs and activities. Currently this subgroup consists of one series -- records transferred from the Lane County Extension office in 1998 due to smoke damage. They span 1940 to 1991 and consist of an annual report, 75th anniversary of Extension materials, newspaper clippings, special events records, newletters, and scrapbooks.