Lamar Valley on a summer evening in Yellowstone National Park, Wyoming, United States of America. Lamar Valley on a summer evening presents the best of Yellowstone. It is home to nearly all of the creatures of the Park. It contains a wild free flowing river, uncounted springs, ponds, and small streams, a major feature of the central Rocky Mountain chain (the Absaroka Mountains), and rich stands of grasses, forbs, shrubs and trees. The comfortable temperature and still air of an evening makes it a perfect place to relax and enjoy the Park.