The following important events affected political boundaries, record keeping, and family movements in Ontario.
- 1610: The first sighting of what is now Ontario by Henry Hudson.
- 1668: Rupert's House,The first Hudson's Bay Company station was built on James Bay.
- 1670: The Hudson's Bay Company was chartered.
- 1759: Fort Niagara was captured by the British.
- 1783: The first United Empire Loyalists arrived in Ontario.
- 1784: After the American Revolution, large numbers of Loyalists arrived in newly-surveyed townships along the St. Lawrence River in upper Quebec.
- 1788: Present southern Ontario was divided into four districts: Hesse, Lunenburg, Mecklenburg, and Nassau.
- 1791: The old Province of Quebec was discontinued and divided into two separate colonies, Lower Canada (now Quebec) and Upper Canada (now Ontario).
- 1792: The first parliament began. The four original district names were changed: Hesse to Western, Lunenburg to Eastern, Mecklenburg to Midland, Nassau to Home.
- 1796: The seat of governement was moved to York (later Toronto.)
- 1800: Districts were adjusted to include counties established for the purpose of levying militia and as voting precincts and land registration units. Other municipal functions such as probate registration remained with the districts.
- 1812: At the time war broke out with the United States, two-thirds of the population were non-Loyalists who had been attracted by the offer of free land.
- 1815: Many immigrants arrived from Scotland. A large number settled in Lanark County.
- 1824-29: The construction of the first Welland Canal.
- 1841: The Act of Union established a single combined legislature for Lower Canada (to be called Canada East [Quebec]) and for Upper Canada (called Canada West [Ontario]).
- 1849: In Canada West (southern Ontario), the counties became functioning governmental units when the old districts were abolished. However, townships within counties remain the basic building block of local government in Ontario until after 1954.
- 1857: Ottawa became the capital of the Province of Canada.
- 1867: The Province of Ontario was formed from Canada West and joined the Confederation when the Dominion of Canada was created, uniting Ontario, Quebec, Nova Scotia, and New Brunswick.
- 1876: Alexander Graham Bell invented the telephone at Brantford.
- 1883: Nickel ore was discovered at Sudbury.
- 1910: The provincial hydro-electric commission was formed.
- 1912: Provincial boundaries were moved northward to Hudson Bay.
- 1954: The Municipality of Metropolitan Toronto was created from the southern half of York County, Ontario.
- 1954: The construction of the St. Lawrence Deep Waterway began.
- 1967: Many additional counties, townships, and other local governments began to be abolished in Ontario as various large "regional municipalities" and other metropolitan governments were created.
A detailed history of Ontario is:
Middleton, Jesse Edgar. The Province of Ontario: A History, 1615-1927. Five Volumes. Toronto, Ontario: Dominion Publishing Company, 1927-1928. (Family History Library book 971.3 H2mj; Volumes 1, 2, 5 on microfiche 6048255-57; Volumes 3, 4 on 1320801 items 5-6.) Volumes 3-5 are biographical.
Bibliographies of local histories for Ontario are:
Aitken, Barbara B. Local Histories of Ontario Municipalities, 1951-1977. Toronto, Ontario: Ontario Library Assoc., 1978. (Family History Library book 971.3 A1 no. 86.)
Aitken, Barbara B. Local Histories of Ontario Municipalities, 1977-1987. Toronto, Ontario: Ontario Library Assoc., 1989. (Family History Library book 971.3 H23a; not on microfilm.)
- Niagara Falls Chronicles of Our Early Settlers, 1600-1900
- Handbook of Brockville History, including marriages 1784-1880]
- -- History http://onlinebooks.library.upenn.edu/webbin/book/browse?type=lcsubc&key=Ontario%20--%20History