The big rush in late 1800s
The great emigration wave from Finland and other Nordic countries occured from late 1800s until 1920s. Most Finns originated from Ostrobothnia on the west coast. Most of them took a ship from Hanko (Hangö) to Hull in the UK and then an ocean liner from Liverpool to Ellis Island in New York or to some other destination.
Reasons for emigrating
In the 1800s Finland was still predominantly an agricultural economy. The farms were mostly small, something like the homesteads in America. Many people went abroad for better living. Ostrobothnia was the major origin of the emigrants. Maybe that was due to the proud, courageous and initiative character of the people in the region. American Finns are proud of their heritage and eager to find their roots in more detail.
Russification years 1899-1917, until Finland's independence
Towards the turn of the century, panslavism gained momentum in Russia and cast its long shadow over Finland, too. In 1809 Finland was raised to the family of nations. After 6 centuries of Swedish rule the country was invaded by Russia. Czar Alexander II was enlightened enough to grant Finland the the position of an autonomous Grand Duchy, and to maintain the Swedish model of administration, far superior to that of zcarist Russia. So Swedish remained as the official language of church as well as administratve records until about 1880 when the Finnish language was granted equal position with Swedish. It was only in 1899 when the situation turned threatening. WW I eabled Finland to detach itself from Russia which became the Soviet Union until 1991.
To Canada until 1920
The emigration wave towards Canada began a bit later than to the U.S. Emigrants came to Canadian ports, but also via the United States. Border crossings is a valuable database for tracing those people.