Crater Lake National Park is located in Southern Oregon. As you could probably guess, the main highlight of this park is Crater Lake. This national park is one of the least known and least visited, but it still has some attributes that would attract anybody.
Mount Mazama used to be a volcano that used to be in this same location. However, about 7,000 years ago the volcano erupted and then the mountain collapsed into the newly formed opening. The entire mountain didn't collapse into the hole, so there was a ginormous opening still there. Over the years, that hole has filled with rain water and melted snow forming Crater Lake.
Crater Lake is the deepest lake in the United States at 1,949 feet at the deepest point. The average depth of the lake is 1,148 feet. To put this in perspective, lake Michigan has an average depth of 279 feet. The lake is also the seventh deepest in the world. Surprising, there are also no rivers or streams that go into the lake or out of it. All of the water is direct from rain and snow.
This lake is actually very clean and extremely blue. The water does not stay in the lake for very long. The ground absorbs the water so fast, that there has to be a constant replenishing of the water. The ground absorbs water so fast that plants have a very hard time growing around here. The roots just can't soak up the water faster than the ground does. This lack of vegitation right next to the lake makes Crater lake National Park quite different from other parks. Don't worry though, there are plenty of plants in the park, just not next to the lake.
So when you go visit the park there is plenty to do. Within the park, there are MANY miles of trails to hike. One specifically will take you to a nice place to go swimming in the lake. Also at the lake, you can go fishing. The lake was stocked with fish in the 40s so now people can fish there without a license or without any restrictions. The national park also offers tours of the lake by boat that many tourists take.