Before the construction of a formal jail, various locations were used to house prisoners in the County. During the Rebellion of 1837-1838, the tower of Old St. Paul’s Church, in Woodstock, became a temporary jail for prisoners captured by the local militia. One of the men incarcerated in Old St. Paul’s, Daniel Bedford of Norwich, was eventually found guilty of treason and hanged from the gallows in London.

With the formation of the District of Brock (1839-1849), a government building was needed to carry out the administrative duties of the magistrates of the Quarter Sessions and, later, the duties of District Council. This building was constructed in 1839 on part of the five acres (Court House Square) that had been designated for that purpose by Governor John Graves Simcoe. Besides local administration, the building was also home to the local court of law and had holding cells in the basement for prisoners awaiting their trial. This building remained in use until the 1890s when the present Oxford County Court House was built.

Although the first by-law passed by the newly created District of Brock was entitled “For the completion of the Court House and Gaol of the District of Brock”, it was not until 1853 that Council began planning for an official County Gaol. That same year, the Clerk advertised a contest for the best jailhouse design plans. The first prize was £20 and went to Messrs. Clark and Murray of Hamilton, who were appointed Architects. Several construction contracts were signed with John Addison, and William Filey, for carpenters and joiners, painters, glaziers and ironmongers in order to complete the building. The total cost of the building was £5,000.

Problems with receiving supplies and outsourcing work to various tenders led to the delay of the project and it wasn’t until the latter part of 1854 that the Gaol was complete. However, several interior problems, such as a leaking roof, led County Council to refuse to accept the keys until it was fully ready for occupancy in August 1855. The Oxford Gaol was the fifth jail built in the Province of Ontario. Picton, Belleville, Goderich and London were all constructed from 1834 to 1853.

The gaol/jail was operated by the County until 1968 when the Province of Ontario took over its administration. By 1977 the Province closed the Oxford County Jail and transferred all prisoners to the Elgin-Middlesex Detention Centre, as it was felt that a modern central location would be best for the sake of the prisoners. Concerns over the future of the jail let to the decision to preserve and renovate the old jail into offices for the Oxford County Board of Health. Carlos Ventin, an architect specializing in historic buildings, designed the renovations and addition, while the work was carried out by Gilvesy Construction. The total cost to rebuild and furnish the building was $2,460,000.00. In June 1986, the Oxford County Board of Health took possession of the building. Now the building houses the Woodstock location of Southwestern Public Health.