Located in North-Western Ontario, Thunder Bay District was established in 1871 from Algoma District.
Originally the area was inhabited by the Ojibwa. By the 1670's fur traders were in the area and trading posts were being established. Both the Hudson's Bay Company and Northwest Company did business in this district.
By the 1850's settlers were starting to arrive, and settlement increased in the 1870's when the railroad came.
Timiskaming District (1912+)
Located in South-Eastern Ontario, Prince Edward County was established in 1792 and named for Duke of Kent, Prince Edward Augustus. 1792-1834 it was part of Midland District, 1834-1849 part of Prince Edward District.
Originally this county was part of the mainland. In 1889 the Murray Canal was completed and made Prince Edward County an island.
The first settlers were United Empire Loyalists who arrived in the 1780's.
Located in South-Eastern Ontario, Victoria County was established in 1851 from Peterborough County and named for Queen Victoria.
The area was first opened for settlement in 1821 and the first settlers arrived in 1825. They were Irish Protestants from County Fermanagh, Ireland. They were soon followed by other Irish & Scottish settlers. As with most counties, the southern part was settled first.
In 1858 twelve new townships were added to Victoria County, but seven were removed in 1868 and instead attached to Muskoka District.
Waterloo County (1838-1972) / Waterloo Region (1972+)
Located in South-Western Ontario, Waterloo County was established in 1838 at the same time as Wellington District. Townships from Halton and Simcoe and part of "Indian lands" were taken to create this new district and county. The county seat was Berlin (renamed Kitchener after World War One).
In 1846 was comprised of the townships of Arthur, Amaranth, Bentinck, Derby, Eramosa, Egremont, Guelph, Glenelg, Garafraxa, Holland, Luther, Mornington, Minto, Maryborough, Melancthon, Nichol, Normanby, Peel, Proton, Puslinch, Sydenham, Sullivan, Waterloo, Wilmot, Woolwich, and Wellesley. Many of the townships were later attached to surrounding counties.
In 1972 this county was dissolved and the area became the Regional Municipality of Waterloo.
Welland County (1845-1970) / Niagara Region (1970+)
Located in South-Western Ontario, Welland County was established in 1845 from Lincoln County. The first settlers in this area were United Empire Loyalists. From 1845-1849 it was part of Niagara District.
In 1970 this county was dissolved and along with Lincoln County became the Regional Municipality of Niagara.
Located in South-Western Ontario, York County was established in 1792 in Home District and named in honour of Yorkshire, England. It was part of Home District until 1849.
The county originally encompassed a very large area extending as far north as Lake Simcoe and as far east as Lake Scugog. Areas of York County were later made into the counties of Halton, Ontario, and Peel.
In 1954 part of York County became the Municipality of Metropolitan Toronto, and in 1971 the remaining part of York County became the Regional Municipality of York.