The most important element of a Montreal bagel, to my mind, is the fact that it is baked in a wood-fired oven. The flame heat gives them their characteristic dappled exterior, with tasty brown spots on the top and bottom in particular. The dry heat of the fire creates a more varied texture between the interior and exterior than does the steam heat used to bake New York-style bagels.
Montreal bagels are shaped in a circular, like New York bagels, and both were brought to their respective cities by Eastern European Jewish immigrants at the end of the 19th and early 20th centuries. The differences between them can be explained by regional differences, both between the communities many of the immigrants came from and then the traditions and practices developed in their new North American homes.
The oldest and most famous bagels shops in Montreal are St-Viateur Bagel (263 St-Viateur Avenue West) and Fairmount Bagel (74 Fairmont Avenue West). Other noted Montreal bagel shops include Mount Royal Bagel Bakery, Cote-Saint-Luc Bagel, R.E.A.L. Bagel, Cantor's, Kosher Quality, and Beaubien Bagel.
Until recently Montreal-style bagels were virtually unheard of outside of Montreal, and certainly unavailable. As Jews from Montreal moved to other parts of Canada, though, Montreal bagels followed to Toronto, Vancouver, and other Canadian cities. More recently, Montreal-style bagel shops have opened in select U.S. cities, including Boston and Seattle. Even Brooklyn now has several bakeries selling wood-fired, egg- and honey-dough bagels.
Learn more about How to Eat Like a Local in Montreal here.