Montreal makes an excellent entryway for visiting other cities and destinations in Quebec and northern United States. Remember that you will have to pass the border control if you go to the US, and arm yourself with the appropriate Visas and papers. Add at least one extra hour for the border control.
Quebec City, about 3 hours to the north east on Highway 40, is almost but not quite a day trip. You'll want to stay over, anyway.
Mont Tremblant lies less than two hours north in the Laurentides.
The Eastern Townships are two to three hours straight east.
Explore the Monteregie townships, a short drive east of Montreal.
Ottawa is two hours west by car.
Toronto is more distant, but still a doable six hour drive or a faster 4.5-hour train trip.
Adirondacks is a two and a half hour drive to the south. Adirondacks is the largest park in the contiguous United States and offers outdoor activities like hiking, rafting and skiing.
Boston is a five and a half hour drive to the southeast.
The Chateau Montebello
located an hour and a half west in Montebello, makes for a romantic getaway or stop on the trip to Ottawa.Between December and March there is good downhill skiing in the Laurentians and in the Eastern Townships. There are some very good night-skiing centres such as Ski Bromont and Mont-St-Sauveur.
Tadoussac, about six hours away by car, has great whale-watching
New York City is only a six and a half hour drive directly south.
