This national park has country's biggest lake (10.8 sq. km) at an elevation of 2990 m. The elevation of the park ranges from 1800 m to 4048 m, Chuchemara Lekh is the highest point. The centrepiece is the pristine Lake Rara, also Known as Mahendra Tal, the biggest lake in Nepal. It is so huge that other end of the lake is hard to see.

 The lake is surrounded by richly forested hills, Chuchemara Danda at 4,087 meters is the best vantagepoint to get stunning views of the lake and the thickly forested hillsides and the snow-capped peaks around it. The lake is oval shaped with an eastwest axis and has a maximum length of 5 km and a width of 3 km. 

The maximum depth of the lake is 167 m. The park was gazetted in 1967 to conserve the unique beauty of Lake Rara and to protect a representative sample of flora and fauna of the Humla-Jumla region. Other summits in the park area are Ruma kand (3,731 m.) and Malika Kand (3,444 m.), situated to the north of the lake. Rara comes within the catchment area of the Karnali River, one of the three main river systems of Nepal.

 The habitat supports animals like the red panda, black bear, yellow-throated martin, ghoral, serow and musk deer. There have also been reported sightings of leopard and wolf. The lake attracts migrant wildfowl like teals, pochards and mallards. Resident birds include the Impeyan, kalij and blood pheasant as well as others like the chukkor partridge. Rara is a good destination point for trekking in the west. 

The trail is very much "off the beaten path" and affords glimpses of culture and scenery very different from those in the rest of the country. The centerpiece of the park is the biggest lake of Nepal. Along mountain paths and a series of picturesque villages, one reaches the magnificent banks of Rara lake. The park includes Trans- Himalayan valley with high ridges covered with forest and alpine pastures.