The Altai Tavan Bogd National Park is located in the far West of Mongolia, Bayan -Olgii Province, on the border with China and Russia.
It is stunningly beautiful with breathtaking blue lakes, 4000m + snowcapped peaks, glacier and archaeological sites.
It is best reached from Olgii, where you need to arrange a permit before setting off. It takes a whole day of driving on a very rough track to reach it, which probably explains why so few people make it there, it is indeed totally off the beaten track.
Of particular interest are the 19 km long Potanii Glacier which can only be reached on foot or horseback; Khoton Nuur, Khurgan Nuur and Dayan Nuur, 3 magical lakes; balbals, Turkic stone statues; petroglyphs; Mongolia's highest peak Tavan Bogd Uul(4374m) which you can climb but only with an experienced group as it is fairly dangerous.
As the region is remote it is essential that you hire a knowledgeable local driver who speaks Kazakh, as this is the language spoken in the region. Camping is the best and only way to do it, although you might be able to stay in some locals' gers, but don't count on it. Horse-riding is highly recommended, as it will allow you to see the best the park has to offer, hiking is also great. It is possible for your jeep to come and meet you at each camp in the evening, so you don't have to carry all your gear.
June is a great time of year to visit, as there will still be plenty of ice on the glacier and the mountains will be covered in snow, although if you want to climb Tavan Bogd Uul, August might be better.
Be aware that it gets cold there even in summer, the wind is bitterly cold and the weather can very suddenly change, so always stick together when hiking.