Bents Basin is a protected nature reserve and state park near Wallacia, New South Wales, Australia in the Sydney metropolitan area.

[3] Aboriginal Australians were denizens of the area due to its vicinity to the Nepean River, which featured food and water.

The inn was built in the 1860s and the site is of local importance, as it gives details of western Sydney's history, early road networks and the rise and fall of rural communities in the region.

To the east of the basin is a cleared undulating paddock on the clay soils from the Wianamatta Shale of the Cumberland Plain.

Asplenium flabellifolium, Adiantum aethiopicum, Oplismenus imbecillis, Cynodon dactylon, Tristaniopsis laurina, Casuarina cunninghamiana, Microlaena stipoides, Syncarpia glomulifera, Glochidion ferdinandi and Ceratopetalum apetalum.

[8] The park is popular for swimming, kayaking, bushwalking, camping (with 100 tent sites), barbecuing, picnicking and fishing.

The basin is renowned for its dangerous and powerful undercurrents, which have been known to suck swimmers down to the bottom of the 20 metre lagoon, resulting in a number of serious and fatal drownings in recent years.