Understanding the changing boundaries of Ontario’s municipalities is crucial in knowing where to look for civil records. This page attempts to explain these changes as they apply to the modern Durham Region; the area this branch of the O.G.S covers. This works in reverse chronological order, as genealogy is researched.
- The Contemporary Era
- The Old Counties
- The Original Districts
The Contemporary Era
1974 – Present: Regional Municipality of Durham
The current Regional Municipality of Durham was formed in 1974 when portions of Durham and Ontario counties were combined. It consists of eight municipalities:
- Ajax – Amalgamation of Town of Ajax and portions of Pickering; of the former Ontario County.
- Brock – Amalgamation of Cannington, Brock and Thorah; of the former Ontario County.
- Clarington – Renamed from Newcastle in 1993, an amalgamation of Bowmanville, Newcastle, Clarke and Darlington; of the former Durham County.
- Oshawa – Amalgamation of the Oshawa and East Whitby; of the former Ontario County.
- Pickering – Losing the South-East portion to Ajax, and the portion West of Rouge River to Scarborough (Toronto); of the former Ontario County.
- Uxbridge – Amalgamation of Uxbridge and Scott; from the former Ontario County.
- Whitby – From the former Ontario County.
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In the creation of the regional municipality, portions of the former Durham and Ontario counties transferred to other regions. These areas are not covered by the Durham Branch of the O.G.S., though there will be many shared genealogical resources with areas that are.
Transferred out of Durham County:
- Manvers to Victoria County [Kawartha OGS]
- Cavan to Peterborough County [Kawartha OGS]
- Hope to Northumberland County [Kawartha OGS]
Transferred out of Ontario County:
- Rama to Simcoe County [Simcoe OGS]
- Mara to Simcoe County [Simcoe OGS]
- Pickering’s West Rouge and Port Union to Scarborough [Toronto OGS]
The Old Counties
For the majority of modern Ontario history, today’s Durham Region was referred to by two counties: Durham County and Ontario County. Both these counties existed at some level of municipality for over a century; Durham for 181 years, Ontario for 121. For the purposes of this timeline, the region’s history will be divided into those two county areas. The histories of now unrelated areas, such as Northumberland and York, will be omitted.
Durham County Region
1850 – 1973: United Counties of Northumberland and Durham
In 1850, the United Counties of Northumberland and Durham was formed when the province abolished the districts system in favour of independent counties. During this period Durham County consisted of six townships:
- Cartwright
- Cavan
- Clarke
- Darlington
- Manvers
- Hope
1802 – 1849: Newcastle District
Prior to the abolition of the districts system, Durham County was part of Newcastle District. The district was formed in 1802 when Durham and Northumberland counties detached from Home District. In the first few decades of this period, county lines were changing rapidly as the area went through multiple expansions and reorganizations.
1841 – 1849
In 1841, the northern portion of the district split off, leaving Durham County with the same six townships that lasted until 1973. The portion that split from Durham County to form Peterborough County consisted of six townships:
- Eldon to Peterborough County [Kawartha OGS]
- Emily to Peterborough County [Kawartha OGS]
- Fenelon to Peterborough County [Kawartha OGS]
- Mariposa to Peterborough County [Kawartha OGS]
- Ops to Peterborough County [Kawartha OGS]
- Verulam to Peterborough County [Kawartha OGS]
1834 – 1841
In 1834, Newcastle District incorporated loose townships into Durham and Northumberland counties. Durham County gained three townships and at this time consisted of twelve townships:
- Cartwright
- Cavan
- Clarke
- Darlington
- Eldon – Newly added
- Emily
- Fenelon – Newly added
- Hope
- Manvers
- Mariposa
- Ops
- Verulam – Newly added
1816 – 1834 this could be split into two sections if a date and/or map is found
In 1816, three new townships were created in Durham County. Sometime between 1816 and 1826, Durham also gained three townships that were previously loose within Newcastle District. Durham County at this time consisted of six, and later nine, townships:
- Cartwright – Created in 1816
- Cavan – Created in 1816
- Clarke
- Darlington
- Emily – Added before 1826
- Hope
- Manvers – Created in 1816
- Mariposa – Added before 1826
- Ops – – Added before 1826
1802 – 1816
In 1802, Durham County was integrated into the newly formed Newcastle District. During this period Durham consisted of it’s only three townships:
- Clarke
- Darlington
- Hope
1792 – 1802: Home District
In 1792, counties were first introduced in Upper Canada which was the origin of Durham County and it’s three oldest townships. During this period, Durham was part of the larger Home District, renamed from Nassau District as part of the county introduction system.
- Clarke – Newly created
- Darlington – Newly created
- Hope – Newly created
Ontario County Region
Ontario County existed in name from 1852-1973; prior to that the region was part of York County. The remaining portions of York will be omitted from this history, as they are covered by the York and Toronto Branches of the O.G.S.
1852 – 1973: Ontario County
Ontario County was created in 1852, alongside Peel County, by a three-way division of York County. The three counties remained united briefly before becoming independent.
1854 – 1973: Ontario County
Ontario County was independent from 1854-1973. During this period the municipalities within Ontario County reorganized many times. The area that is now Oshawa and Whitby townships, began as a unified Whitby; lost the Town of Whitby which became it’s own municipality; split in half, creating East Whitby; and eventually re-amalgamated with the Town of Whitby. Ajax was also formed during this period from a portion of Pickering.
Rama and Mara were originally amalgamated into a single township upon the creation of Ontario County in 1852. Later, the united Rama and Mara were reincorporated as independent townships.
- Ajax – Incorporated in 1955 from the South-East portion of Pickering
- Brock
- East Whitby – Incorporated in 1857 from the East side of Whitby
- Mara – Reincorporated in [unknown year, perhaps 1854 or 1869]
- Pickering
- Rama – Reincorporated in [unknown year, perhaps 1854 or 1869]
- Reach
- Scott
- Scugog – Incorporated in 1856 from Scugog Island that had been split between Reach and Cartwright Townships
- Thorah
- Uxbridge
- Whitby – Amalgamated in 1968 from Town of Whitby and Whitby Township
- Town of Whitby – Incorporated in 1855
1852 – 1853: Ontario County (of united Counties of York, Ontario & Peel)
Ontario County was formed in 1852 from nine townships that had been incorporated within the previous York County. Rama and Mara were incorporated as single united township during this time, but later reincorporated as separate municipalities.
- Brock
- Pickering
- Rama and Mara – Incorporated in 1852
- Reach
- Scott
- Thorah
- Uxbridge
- Whitby – Incorporated in 1852
1849 – 1851: York County
The eight townships in York that would become Ontario County were incorporated through a proclamation effective January 1, 1850 under the terms of the Baldwin Act, Chapter 81, Canada Statutes, 1849.
- Brock
- Mara
- Oshawa, Village of
- Pickering
- Reach
- Scott
- Thorah
- Uxbridge
1792 – 1849: Home District
The Original Districts
The histories of Durham and Ontario counties intersect within the Home District.
1788 – 1792: Nassau District
in 1788, the Nassau District was created within the Province of Quebec