This collection consists of reports by city, local, and regional planning agencies spanning approximately from 1873 to 2000. The geographic range of the reports is global, but is focused mainly on Southeastern Connecticut and New Haven, though many smaller towns and cities in Connecticut are also represented. More general reports about the New York region and other states, socioeconomic data about the United States, and scattered documentation about urban planning in other countries are also part of this collection.

The Douglas W. Rae papers consist of interviews of members of the Howard family conducted from 1988 and 1989. The interviews document the social and economic experiences of an extended African American family in New Haven from the 1950s to the 1980s. The papers also include account books from Rae's tenure as chief administrative officer of the city of New Haven, Connecticut, from 1990 to 1991 which contain notes, reports, meeting minutes and daily memoranda.

The collection comprises records of the Greater New Haven Coalition for People, a grassroots organization that advocates for lower and middle income residents of New Haven, Connecticut. Materials include correspondence, financial and fundraising records, files on topics and events that the Coalition worked on, and posters and protest signs. Materials date from 1981 to 2014.

The collection consists of the personal papers of James F. Ahern, documenting his position as chief of police for New Haven, Connecticut. Included are materials related to student and police activities during May Day 1970 at Yale University, wiretapping by the New Haven police, and Ahern's role as a member of the President's Commission on Campus Unrest in 1970.

The papers consist of reports, drawings, and correspondence, documenting the professional work, particularly city renewal planning, of Maurice Emile Henri Rotival during the years 1944-1963.

Project files, minutes, correspondence, and property records, documenting the work of the New Haven Redevelopment Agency, primarily from the 1950s to the 1980s.

The Richard C. Lee Papers document the public years of one of the best known mayors in the United States. The bulk of the papers cover the period 1954-1969, when Lee was mayor of New Haven, although the papers span the dates 1934-1983.

Materials in the Catherine Roraback collection of Ericka Huggins papers document the activities of both Catherine Roraback and Ericka Huggins during the New Haven Black Panther trials. A majority of the collection contains Catherine Roraback’s legal files related to Ericka Huggins's trial, including memoranda on prison conditions, statements, depositions, affidavits, and FBI reports. Materials belonging to Ericka Huggins includes poems, correspondence, and other writings created during her imprisonment. Communist reading material requested by Huggins such as The Selected Writings of Mao Tse-Tung (1968) are also included.

The collection contains bound volumes of manuscript meeting minutes for the New Haven East Association and the Consociation of the County of New Haven, New Haven East Consociation, Association of the County of New-Haven, and New Haven Union Association of Congregational Ministers. Also present are other records and papers related to the business of the association, its member churches and foreign missions, its mutual improvement societies, and a painted metal box that formerly held the records.

The collection contains bound volumes of manuscript meeting minutes for the New Haven West Association, along with other records and papers related to the business of the association such as missions to New York State and cases regarding specific clergy members. Also present are meeting minutes for the New Haven West Conference of Churches, the constitution of the Consociation of the Western District of New Haven County, a printed memorial to Rev. William Patton, and a decorated trunk that formerly held the records.

Part of the new Mayoral Papers Collection at Southern Connecticut State University's Department of Special Collections and Archives, the Mayor John DeStefano Jr. Papers are currently being digitized and made available online.