Shannons Flat is a locality in the Monaro region of New South Wales, Australia. The town is in the Snowy Monaro Regional Council local government area, sandwiched between the southern border of the Namadgi National Park in the Australian Capital Territory and the Murrumbidgee River. Shannons Flat also adjoins the NSW suburbs of Yaouk, Bolaro, Murrumbucca, Bredbo and Billilingra. It is about 308 kilometres (191 mi) south west of the state capital, Sydney, and 70 kilometres (40 mi) from the Australian national capital of Canberra. It is just over 40 kilometres (25 mi) north west of the regional centre, Cooma.
At the 2011 census, Shannons Flat had a population of 208.