Originally formed as Jasper Forest Park on 14 September 1907, Jasper national part is Canada's largest Rocky Mountain park, spanning 10 878 square kilometres of western Alberta (that's 4200 square miles if you're south of the border). In it are 1200 kilometres of hiking trails (660 miles). To the south is Banff National Park, which is connected to Jasper by the Icefields Parkway. The parkway travels along the continental divide, and the Columbia Icefield borders it at the southern end of the park. Don't walk out on the glacier, you'll probably die. If you feel the need to be out on the glacier, go on a guided tour. The park also contains a lot of animals, like elk, bighorn sheep, mule deer, grizzly bears, mountain lions, wolves, and wolverines. Steer clear of these animals, because they are yet another way to get killed in the park. On a related note, be very careful where you step whilst inside the town of Jasper. Especially when barefoot or while wearing nice shoes.
The park contains several nifty places to check out. Be sure to see the highest mountain in Canada, the 3747 metre Mount Columbia. The hydrographic apex of North America, the Columbia Icefield, where water flows to three different oceans from one point is another nice geographical feature. While on the subject of big icy things, the Athabasca glacier in the park is the most accessible glacier in North America. It also contains the Maligne Valley karst, which is the longest underground drainage system known in Canada. The only sand-dune ecosystem in the Four Mountain Parks at the Jasper Lake dunes is another place to see. Alberta's northernmost Douglas-fir trees are in the park at Brûlé Lake. If wildlife is your thing, you can see the last fully protected caribou range in the Rocky Mountains. The largest glacial fed lake, the 97 metre deep 22 kilometre long Maligne Lake, is another beautiful place to visit. Seriously, bring lots of film to this park, there are many more places than mentioned in this list.
Jasper National Park, like most national parks, charges admission fees to keep it going. The fees are low (as of this writing, the highest individual fee is six Canadian dollars plus tax for an adult) per day, and the park is more than worth it (in my opinion). The campground and fishing fees are pretty decent too.
Be sure to behave in the park. Don't take anything natural. That means flowers, antlers, bits of wood, rocks, anything. This is a sensitive ecosystem. While you're at it, don't leave anything unnatural. Put litter in its place. Don't bother the animals. When they say don't feed the bears, they mean don't feed the bears. Keep your food in vehicle trunks or bear-proof containers. Or any other animal, even if it looks tame. Keep your pets leashed. They don't know to follow the rules regarding bothering animals. Keep an eye on pets, or you may be violating the rule regarding feeding the animals. Only camp in designated areas. Rule infractions can be reported by phoning toll-free 1-888-WARDENS.