1. Jackson Lake is a stunning natural lake located within Grand Teton National Park in Wyoming, USA. The lake covers 15,000 acres and is the largest lake in the park. It is a major feature of the park, offering breathtaking views of the Teton Range reflecting off the crystal-clear waters.

Boating, fishing, and kayaking are popular activities on Jackson Lake, and there are several marinas and boat ramps around the lake. Swimming is also allowed in designated areas. Camping is available at campgrounds along the shores of the lake, providing a unique outdoor experience surrounded by the beauty of the Grand Tetons.

2. Grand Teton National Park is open 24 hours a day, seven days a week. The park visitor center can provide more information on specific opening hours for facilities and services. For more information, you can contact the Grand Teton National Park headquarters at (307) 739-3300.

3. There is an entrance fee to Grand Teton National Park, which is $35 per vehicle for a seven-day pass. Annual passes and other options are also available. Visitors can access Jackson Lake by car via the main park road, which provides easy access to various points around the lake. Boat rentals and tours are available at the marinas for those interested in exploring the lake from the water.