The Leon Williams Papers document three decades of William's public service career, and includes news clippings, photos, correspondence, invitations, public appearance forms, public opinions, campaign information, reports, ordinances, plaques, certificates of achievement, various committee files, and conference minutes. During his time on city council, Williams advocated land use programs, revitalization of older neighborhoods, and the use of public transportation. The majority of the material dates from about 1970 to the late 1990's, and highlights these aspects of Williams' career. The collection is divided into five series:  Campaign Files (1969-1994), Conference Files (1974-2000), Professional Files (1966-2003), Personal Files (1961-2006), and News Clippings (1969-2002).

The Campaign Files (1969-1994) document Williams various campaigns, and includes pamphlets, correspondence (including congratulation messages), volunteers, topics, district maps, and voter data. The files are arranged chronologically by campaign years, followed by alphabetical general files that contain voter information and election topics. Williams' later campaigns (late 1980's, early 1990's) are poorly documented.

The Conference Files (1974-2000) document the various conferences Williams participated in. These files include meeting minutes, topics discussed at the conferences, notes, and conference handouts.The best documented conferences include CSAC and NACO conferences, but in general the Conference files are fairly small and superficial.

The Professional Files (1966-2003) document Williams' career in public service. This series is divided into four chronological sub-series, the Urban League Files, the District IV Files, which make up the bulk of this series, the MTDB Files, and the California Constitutional Revision Committee Files.  The Urban League sub-series document the early part of Williams' public service career and is organized alphabetically. The sub-series includes correspondence, police reports, Citizen Interracial Committee, and project files. Although these files are sparse in number, they provide insight into how William's began his public career. They also serve to highlight particular events and issues in the San Diego African American community during the late 1960's, such as the Morse High School student arrests. The District IV Files provide extensive documentation of Williams' career on the City Council. These files are divided into Chief-of-Staff Files and General Files.  The Chief-of-Staff Files were the records of Williams' Chief-of-Staff, Don Abel, and are arranged into two alphabetical sub sub-series: General Files and Subject Files. The General Files sub-series is likewise organized by alphabetical subjects.  Both the Chief of Staff Files and the General Files often overlap one another and detail various community projects, correspondence, committees, public opinion cards and ordinances. For example, the SAFE committee, Human Relations Commission, Southeast Economic Development Corporation (SEDC), growth management, airport issues, Blacks Beach, AIDS, and CSAC, are some of the main subjects covered by the District IV files. The public opinion cards give wonderful examples of what San Diegans thought about major San Diego issues, such as, the Claremont hospital and expanding the central library. In contrast, the MTDB Files document major transportation decisions, correspondence, maps, and reports that mainly relate to the San Diego Trolley and its eastward expansion. These files date from 1989 to 2004 and are organized alphabetically into two sub sub-series: General Files and Reports. The General Files contain correspondence, plans, news clippings, and subject files. The Reports consist of reports regarding environmental impact, transportation needs, and specific trolley stations.  There is limited documentation of San Diego State University's trolley station specifically, but good documentation of the Mission Valley extension line in general. The California Constitutional Revision Committee Files, on the other hand, document all its major conferences, and the topics discussed at those conferences, including possible amendments. These files include, conference materials and handouts, agendas, subject files, possible amendments and revisions, and meeting minutes.  These files are divided into alphabetical General Files and chronological Meeting Files.

The Personal Files (1961-2006) mainly document events, topics of interests, and involvement in organizations not specific to Williams' professional career and is organized alphabetically. The series contains photos; correspondence; invitations to community events, private gatherings, and state and federal conferences; public appearance forms; topics of interest; certificates of achievement; award plaques, and non-governmental organizations that Williams participated in. There is extensive documentation of Williams' invitations, public appearances, and achievements, especially during the early 1990's.

The News Clippings (1969-2002) provide excellent documentation of events and projects Williams, the MTDB, and the City Council were involved with. There are also clippings regarding Williams' personal achievements, and issues that Williams' was specifically interested in, such as AIDS. There are, however, very few articles from the late 1960's. The majority of the news clippings are from the mid 1970's to the early 1990's, although there are some clippings from the early 21st century and the early 1970's. These files are organized chronologically.