In Canada (Upper Canada and Lower Canada before the Union Act of 1841), the "Great Migration" was a period of accelerated immigration. In the early 1800s, innovations of the Industrial Revolution began to automate many of the jobs that employed the lower classes. Starting around the end of the Napoleonic Wars in 1815, the jobless and hungry were lured to travel to the "New World" from Great Britain and Ireland. This was partly facilitated by England's hunger for lumber -- ships brought timber from the New World, and carried immigrants on the return trip to Canada. By 1830, almost 30,000 people annually were arriving in the Canadas, mostly via Québec City. By 1851, almost 700,000 immigrants had passed through Québec City from ports in England, Ireland, and Scotland with some 60% of those arriving from Irish ports. This influx changed the language and cultural balance of the Canadas from predominantly French to British.
Grosse Île tragedy
When a terrible outbreak of cholera spread through Britain in 1832, authorities hastily set up a quarantine station at Grosse Île, an island in the St. Lawrence river approximately 50 km downstream from Québec City. A particular tragedy took place at Grosse Île in 1847, during the height of the Irish potato famine. With over 90,000 immigrants arriving after fleeing the famine, an outbreak of typhus swept the island, claiming over 5,000 lives at the station and on quarantined ships anchored nearby (compared to a few dozen deaths in any other year).
Data from Parks Canada's Grosse Île and the Irish Memorial National Historic Site of Canada