Mares Forest National Park, Nature reserve in Upper Lachlan Shire Council, Australia.

Mares Forest National Park is a protected nature reserve in Upper Lachlan that covers approximately 26 square kilometers of diverse habitats. Kurrajong trees, rocky outcrops, and native grasslands define the landscape across the Southern Tablelands region.

The reserve was established in 2010 as part of New South Wales conservation efforts to protect the region's natural habitats. This protection aimed to safeguard the biodiversity of the Southern Tablelands for the future.

The park lies in the country of the Gundungurra, whose name is preserved in the nearby locality of Bannaby and in the Wollondilly River that forms its western edge. The kurrajong trees scattered through the reserve were used by Aboriginal people for fibre and fodder. The park's name recalls the Mares family, early settlers in the Southern Tablelands.

The park lies about 130 km west of Sydney and 50 km northeast of Goulburn, west of the Wollondilly River, between Blue Mountains National Park to the north and Tarlo River National Park to the south. It has two parts: a larger southwestern section and a much smaller northeastern one. No visitor facilities or marked trails are recorded in the sources, so plan access and navigation yourself.

During summer evenings, kangaroos, wallabies, and wombats emerge to forage across the parkland. This active period offers visitors the chance to observe these animals in their natural behavior.