Until 1824 the County of Lanark was a part of Leeds County.
Both Leeds and Grenville were first organized as counties in 1792 as sections of the Eastern District of Upper Canada. In 1800 the Eastern District was split because distances and administration work was too great and Leeds and Grenville became part of the new Johnstown District.
Leeds took its name from Francis Osborne, 5th Duke of Leeds (that is the city of Leeds in West Yorkshire, England). Grenville was named in honour of William Wyndham Grenville, 1st Baron Grenville, Secretary of State in 1790.
The first settlers were Loyalist from the United States who arrived as early as 1784-- many were recently disbanded officers and soldiers from serving British army companies after the Revolutionary War.
Western Leeds County was opened for settlement in 1788 and in the 1790s the "rear" townships were opened. Settlement was slow until after the war of 1812 when disbanded soldiers and British emigrants settled in the area. A majority of the British emigrants were from Scotland and arrived in 1816. Even more settlement occurred during the 1820's after the construction of the Rideau Canal.
A detailed history of the Leeds and Grenville area can be found on the Wikipedia page for Brockville, the principal town of the two counties.
In 1849-50 the District system of administration was abolished and Leeds and Grenville Counties were formed into the United Counties of Leeds and Grenville. At this point the province of Ontario was known as Canada West. It was to remain with this name until Canadian Confederation in 1867 when it took the name Ontario.
Townships and Municipalities
The original townships of Leeds county were
and the original townships of Grenville were
Since 1998, when Leeds and Grenville was restructured into a lesser number of "townships" or "municipalities", the list for the two counties is as follows:
Separated from the county administration are
The new townships will be described as municipalities in the List of Contained Places.
The map of Leeds County circa 1951 and the map of Grenville County circa 1951 from Ontario Archives locates the individual townships, towns and villages. A handy rule of thumb: Leeds is on the left when looking from Lake Ontario.
The primary source for basic documents (vital statistics, land records, wills) for people who lived in the Province of Ontario is the Archives of Ontario, 134 Ian Macdonald Blvd, Toronto, Ontario, Canada M7A 2C5.
Civil registration did not begin in the province until 1869. Before then there may be church records of baptisms and burials. For the most part these are still held by the denomination who recorded them. Copies of marriage records made pre-1869 had to be sent by individual clergymen to the registrar of the county in which the marriage took place. These marriage records are available through Ontario Archives, on micorfilm through LDS libraries, and on paid and unpaid websites, but because they were copied at the registrars' offices, they cannot be considered a primary source.
Vital Records after 1869
Birth, marriage and death registrations are not open to the public until a specific number of years after the event occurred. Births to 1914 are now available [October 2012]; dates for marriages and deaths are later. Birth and death registration was not universally carried out in the early years after its adoption. Deaths were more apt to be reported than births for several years. The more rural the area, the less likely it would be that these happenings were reported to the authorities.
Land Records and Wills
Information on how to access land records and wills is best sought on the Archives of Ontario website. An ancestor's land holding might be found on Canadian County Atlas Digital Project if he was in occupancy circa 1878.
Association for the Preservation of Ontario Land Registry Office Documents (APOLROD). A list of Land Registry Offices for all Counties of Ontario.
The original censuses are in the hands of Library and Archives Canada. All of the original census (1851-1911) images are online with the exception of that for 1861. Not all of them are indexed. Later censuses are not yet available. Census divisions were redrawn as the population increased and more land was inhabited.
E-books and Books
Some websites with more local information on Leeds and Grenville Counties