Kalesar National Park, National park in Yamunanagar district, India.

Kalesar sits in the hills at the edge of the plain and covers more than 5,200 hectares of wooded terrain with sal trees, acacias, and palms. Narrow trails wind through the dense green and sometimes open onto clearings where animals gather to drink.

Ahmad Shah Abdali camped at Pinjore Gardens in 1765, and the British soldier Rollo Gillespie camped in these hills in 1807 to hunt tigers. By 1892–93 excessive hunting had reduced the numbers of tigers and panthers, and Sirmur State banned hunting in 1913. The wildlife sanctuary was notified on 13 December 1996 and the national park on 8 December 2003.

The park takes its name from the Kalesar Mahadev temple inside it, whose name is a corrupted form of Kaleshwar, a name of Shiva. A later Shiva temple stands north of it. In January 2019 the Haryana government included the temple in an INR 1200 crore Morni-to-Kalesar tourism plan, alongside Kapal Mochan Tirth and the Sharda Mata temple of Chotta Trilokpur.

The park routes are intended for offroad vehicles since steep sections and unpaved surfaces would challenge ordinary cars. Morning and evening drives offer the best chance to see animals when they are active.

A guesthouse from colonial times stands in the woods and was once used by British officials during their travels. From its veranda you can spot the river course at the foot of the hills on clear days.