New reports say hydrofracking threatens groundwater resources.

The panel will review the risks of oil pipelines running under the state's rivers, a move prompted by the oil spill in the Yellowstone River.

The EPA and State Department have now clashed over the proposed pipeline twice in two years, muddling recent indications that its approval might be imminent.

A few trails in the U.S. enjoy a high profile because of their overall length, remoteness, amazing scenery or historical significance. These classics of America's hiking scene draw much-deserved attention from both casual hikers and hard-core trekker

Here are seven of our favorite waterfalls in national parks.