Brock District was separated from the London District in 1839. It included Oxford County The area was first settled in 1793.
The Archives of Ontario has produced a series of maps illustrating the growth of the District system across the province. Each map ought to be expanded to its maximum size in order to benefit from the information it contains. Return to the collection using the "back" button on your browser.
Ontario Districts: an Explanation
When Upper Canada was formed in 1788 it was immediately divided into four districts: Hesse, Nassau, Mecklenburg and Lunenburg. In 1792 these names were changed to Western, Home, Midland and Eastern respectively. The expansion in population of the province, and in the area settled, obliged the number of Districts to increase. By 1849 there were twenty individual districts, each with a number of counties under its jurisdiction.
After 1841, when the government of Upper Canada was reorganized and the province became known as Canada West, some of the responsibilities of the districts were transferred to local municipal councils in cities and towns (e.g. property tax collecting), although the districts still retained complete control over judicial matters.
From 1788 until 1849 in the area which is now Ontario, the District was the layer of government responsible for all judicial and administrative functions that could be carried out at a level below that of the province itself. Counties existed in the province from 1792, but they were little more than electoral and census divisions.
In 1849 the Districts were abolished and their functions were taken over by the individual counties or by united counties working within one municipal administration.
Most of the government documents the genealogist may require—those dealing with land, the registration of marriages, and minor criminal proceedings--will have been produced by the District before 1849 and by the Counties after that date. Serious land conflicts, or those concerning more than one District, will have found their way into Provincial Records. The same will have been true of criminal matters. Divorce was not even a provincial matter, but a federal one, until 1930.