Onneto is located at the westernmost end of Akan Mashu National Park, and is a beautiful lake with a circumference of 2.5km located at the foot of Mt. Meakan. Its beauty and primeval charm attract many tourists. Depending on the season and weather, and by viewing angle, it is a mysterious lake whose color changes to clear blue, emerald green, and dark blue.

On the west side of the lakeside, there is a wooden observation deck, from which Onneto can be overlooked with Mt. Meakan and Akan-Fuji as a backdrop. Around the lakeside, walking paths are maintained, and you can fully enjoy the untouched great nature surrounded by primeval forest. In the vicinity, there are Onneto Yu-no-Taki (Onneto Hot Water Falls), Meakan Onsen (Meakan Hot Spring), and a national campsite (until the end of October) which also serves as a base for climbing. From June, Reiwa 4, adjacent to the campsite, the Onneto Campsite Rest House opened, and campsite usage reception, tourist information, rest area, sales and rental of outdoor goods etc., and light meal/drink provision etc. are carried out.

Annually, in years when several conditions are met, such as little snowfall, between late November and early December, beautiful ice formation can be seen. Beautiful scenery such as the sound of the lake crying, ice bubbles, and Mt. Meakan reflected on the frozen lake surface can sometimes be seen.

In the lake, there are several spots where gas and hot springs well up, and there the ice may be thin, or there may be no ice. Also, the thickness of the ice on the lake surface differs depending on the year and season, so please be sufficiently careful not to fall into the water or drop things into the lake (non-powered boats (such as canoes) also cannot enter, so what is dropped cannot be retrieved permanently).

Since there are many people who come to see the quiet and untouched natural environment, please refrain from making loud noises and being noisy, or engaging in acts that would bother other people.

Furthermore, based on the Natural Parks Act, entry of powered boats and snowmobiles etc. into Onneto is regulated. Also, in order to maintain Onneto's original tranquility and primitive scenery, we ask for your cooperation to refrain from the use of non-powered boats such as canoes and water sports including swimming.