Kingston is a city in Eastern Ontario located where the St Lawrence River leaves Lake Ontario. The city is located at the mouth of the Cataraqui River and is connected to Toronto, Ontario and Montreal, Quebec via ON-401(MacDonald Cartier Freeway). ON-401 West: Toronto, ON-401 East: Montreal. The city is located 250 km (150 miles) northeast of Toronto and 290 km (175 miles) southeast of Montreal. The city is served by Norman Rogers Airport by which Air Canada offers flights to Toronto, Ontario's Pearson International Airport in Mississauga, Ontario.