Cotter Flat is a highly regarded backcountry campsite situated along the Cotter River in the Australian Capital Territory, reached at roughly the 15–16 km mark of the 32 km Cotter Flats trail.

The site features flat, grassy ground kept naturally short by a resident kangaroo population, reliable water access from the river, and good shelter from the wind — making it one of the more comfortable overnight stops in the region.

Campers should pitch tents among the small wattle trees rather than beneath large eucalypts, as falling limbs and tree drops are a real hazard, particularly during high winds or heavy rain.

Note that camping is required to be more than 500 metres from the rangers hut located on the opposite side of the river.