It was common for ancestors to arrive first in Canada and then come to the United States. That’s one aspect of immigration research. There is another aspect sometimes people don’t think about. This is that both Americans and Canadians went back and forth for any number of reasons. Sometimes we forget Irish had family members in any number of countries. In the case of North America, they could visit each other, and often they did.
This archive of records have been indexed and digitize in the database “Border Crossings: From Canada to the U.S., 1895-1956”: www.ancestry.com Don’t let the late date detour you away from this source. Quite the contrary if you think about it. You can have someone who emigrated from Ireland in the 1860s or 1870s, go visit family in either country by the 1890s or after the turn of the century. If they are entering the United States legally, they technically should appear on these border crossings.
The records will provide name, residence, relatives, birth places, age and point of entry. Remember, the border crossings are mainly, but not exclusively, points of entry across land. Points of entry stations were not consistent for the entire span of years. These include:
Maine: Bangor, Calais, Easton, Eastport, Fort Fairfield, Fort Kent, Houlton, Jackman, Lubec, Madawaska, Van Buren, Vanceboro
Minnesota: International Falls, Baudette, Duluth, Mineral Center, Noyes, Pigeon River, Pine Creek, Roseau, Warroad
Montana: Babb, Chief Mountain, Cut Bank, Del Bonita, Gatweay, Great Falls, Roosville, Sweet Grass
New York: Alexandria Bay, Buffalo, Cape Vincent, Champlain, Clayton, Fort Covington, Hogansburg, Lewiston, Malone, Moers, Morristown, Niagara Falls, Nyando, Ogdensburg, Rochester, Rooseveltown, Rouses Point, Thousand Island Bridge, Trout River, Waddington
North Dakota: Northgate, Pembina, St. John, Walhalla
Vermont: Newport, St. Albans
Washington: Anacortes, Danville, Ferry, Lynden, Laurier, Marcus, Metaline Falls, Northport, Oroville, Port Angeles, Sumas
I have successfully utilized this resource. Most of my success has come from researching people who were crossing the border decades after they had already emigrated from Ireland.