Tswaing (Tswana for "place of salt"[1]) is an impact crater enclosed by a 1,946 ha nature reserve, situated in northern Gauteng province, South Africa.

The crater and reserve are situated on a base of ancient granite of the Bushveld Igneous Complex, some 40 km to the north-northwest of Pretoria (just north of Soshanguve).

[3] The impactor is believed to have been a chondrite or stony meteorite some 30 to 50 m in diameter that was vaporised during the impact event.

[3][4] Morokweng impact structure, another South African crater of chondrite origin, lies north-west of Vryburg.

Between 1912 and 1956 brine was pumped from the floor of the crater by the company SA Alkali Ltd. in order to extract soda and salt.