At its formation in 1929, Grand Teton National Park encompassed just six main lakes at the foot of the park's major peaks, but with the expansion of the park there are now 44 named lakes within the boundary, and countless smaller unnamed lakes and ponds. The peaks were raised in relatively recent geological time and carved by glaciers in the ica age. Most of the lakes in the park were formed by glaciers, which carved out the valleys they sit in, and where glacial morraine formed the dams that created the lakes. The largest lakes are still found at the base of the Teton Range. In the northern section of the park lies Jackson Lake, the largest lake in the park at in length, wide and deep. Though Jackson Lake is natural, the Jackson Lake Dam was constructed at its outlet before the creation of the park, and the lake level was raised almost consequently. East of the
Jackson Lake Lodge lies
Emma Matilda and
Two Ocean Lakes. South of Jackson Lake,
Leigh,
Jenny,
Bradley,
Taggart and
Phelps Lakes rest at the outlets of the canyons which lead into the Teton Range. Within the Teton Range, small alpine lakes in
cirques are common, and there are more than 100 scattered throughout the high country.
Lake Solitude, located at an elevation of , is in a cirque at the head of the North Fork of Cascade Canyon. Other high-altitude lakes can be found at over in elevation and a few, such as
Icefloe Lake, remain ice-clogged for much of the year. The park is not noted for large waterfalls; however,
Hidden Falls just west of Jenny Lake is easy to reach after a short hike. A 2005 study of the water quality of the lakes in Grand Teton National Park indicated that the lakes in the park were still considered pristine and that they had not been impacted by air or water pollution.
Human history Paleo-Indian presence along the shores of Jackson Lake is attested from 11,000 years ago in what is now Grand Teton National Park. Jackson Hole valley climate at that time was colder and more alpine than the
semi-arid climate found today, and the first humans were migratory hunter-gatherers spending summer months in Jackson Hole and wintering in the valleys west of the Teton Range. Along the shores of
Jackson Lake, fire pits, tools, and what are thought to have been fishing weights have been discovered. One of the tools found is of a type associated with the
Clovis culture, and tools from this cultural period date back at least 11,500 years. Some of the tools are made of
obsidian which chemical analysis indicates came from sources near present-day
Teton Pass, south of Grand Teton National Park. Though obsidian was also available north of Jackson Hole, virtually all the obsidian spear points found are from a source to the south, indicating that the main seasonal migratory route for the Paleo-Indian was from this direction.
Elk, which winter on the
National Elk Refuge at the southern end of Jackson Hole and northwest into higher altitudes during spring and summer, follow a similar migratory pattern to this day.From 11,000 to about 500 years ago, there is little evidence of change in the migratory patterns amongst the
Native American groups in the region and no evidence that indicates any permanent human settlement.
Lake formation Some 34 million years ago, the forces of the
Laramide orogeny had uplifted a broad part of western
Wyoming into a continuous high
plateau. This region includes areas now occupied by the Teton Range,
Gros Ventre Range,
Wind River Mountains and other mountain ranges to the south and east of the Tetons. Beginning around 13 million years ago in the
Miocene, a 40-mile (64-km) long steeply east dipping geological fault system called the
Teton Fault began to vertically move two adjacent blocks. One block, the Jackson Hole basin, moved downwards while the other block, containing the westward-tilting eastern part of the Teton Range, moved up, creating the Teton massif. This very recent event in geological time created some of the youngest mountains in North America. In the most recent glaciation, known as the Pinedale glaciation in the Rocky Mountains (from 30,000 - 10,000 years ago), the greater Teton and Yellowstone region contained one of the largest mountain glacier ice complexes in the western US. The previous rapid uplift of the Precambrian bedrock of the region and glacial erosion created a dramatic landscape that was carved out by the Pinedale glaciation, leaving significant glacial deposits behind when the ice retreated. The deposits are in the form of moraines, till and outwash. Sediment fill created a region of lakes, creating the natural dams that formed the lakes and also marked the glacial maxima, and marking the glacial retreat. == Recreation ==