* Scottish Highlanders: In the early 19th century, large numbers of Scottish Highlanders immigrated to Ontario, particularly to the Ottawa Valley and Glengarry County. They brought with them their Gaelic language and culture, and contributed to the province's rich tapestry of ethnic diversity.
* Irish: The Irish were another major immigrant group to Ontario in the 19th century. They came in large waves during the Great Famine of the 1840s and the Fenian Raids of the 1860s. Many Irish immigrants settled in cities like Toronto, Kingston, and Ottawa, where they worked in construction, manufacturing, and other industries.
* Germans: Germans were also a significant immigrant group in Ontario in the 19th century. They settled in both rural and urban areas, and contributed to the province's economy and culture. Many German immigrants were farmers, while others worked in trades such as carpentry, brewing, and blacksmithing.
* Chinese: The first Chinese immigrants arrived in Ontario in the mid-19th century, many of them working as laborers on the construction of the Canadian Pacific Railway. They later established communities in cities like Toronto and Ottawa, and played an important role in the development of the province's economy and culture.
* Italians: Italian immigrants began arriving in Ontario in the late 19th and early 20th centuries. They settled in both urban and rural areas, and contributed to the province's economy and culture. Many Italian immigrants were farmers, while others worked in construction, manufacturing, and the service industry.
* Portuguese: Portuguese immigrants began arriving in Ontario in the early 20th century. They settled in both urban and rural areas, and contributed to the province's economy and culture. Many Portuguese immigrants were farmers, while others worked in construction, manufacturing, and the service industry.