Montana's Glacier National Park is a true hiker's paradise, with more than 730 miles (1,174 kilometers) of marked trails within its boundaries. It's such a popular hiking destination that more than half of the people who enter the park are there to set off on foot and explore. The park and its trails are known for impressive mountain peaks, isolated alpine lakes and no shortage of wildlife. The park gets its name from the huge glaciers that helped to shape the park's rock formations 10,000 years ago. In 1850, the park had 150 glaciers, but today there are only 26 remaining. Because of climate change, those are predicted to be gone by the year 2020 [source: NPS.gov]. Like most of our national parks, you'll need a backcountry permit to hike overnight in Glacier, but you don't need to plan a year in advance like the more popular Grand Canyon and Yosemite. Another consideration for hiking in Glacier is the snow line. By mid-June you can hike the lower elevations with no fear, but you'll have to wait until late July for the snow to melt in the higher elevations.http://www.nps.gov/glac/index.htm