Nackara (formerly Tregu) is a locality and former farming town in South Australia, 47 kilometres east of Peterborough on the Barrier Highway.

It was originally proclaimed as the Government Town of Tregu on 2 July 1891 but the name was changed to Nackara in 1940 to match the name of the railway station.

The Nackara township never consisted of more than a few railway cottages, a town store/post office (part of a house), a community hall ('The Nackara Institute'), a Catholic church, a Presbyterian Church, a school, the railway platform, cattle yards and cemetery.

The planned roads didn't ever eventuate, with only dirt tracks through the very dry paddocks.

The area is too dry to support much livestock, so Nackara never grew beyond around 20 families and the township didn't develop.