Pinnaroo is a town in the Murray Mallee region of South Australia, near the border with Victoria 243 km east of Adelaide. Pinnaroo is on the Mallee Highway, and the railway line between Tailem Bend and Ouyen. The roadhouses on the highway are the first food and leg-stretch stop on the bus route from Adelaide to Sydney. At the 2006 census, Pinnaroo had a population of 558.
The town's name is derived from "big man" in a local Aboriginal language.
The railway arrived in the area in 1906. There had not been any significant development in the area before that, as the remoteness and difficulty of getting supplies in and produce out had made it uneconomic to farm before that.
The Border Times is a weekly newspaper published in the town.
The Town has a large variety of sports for a town of 900, such as Australian Rules Football, Netball, Cricket, Tennis, Basketball, Volleyball, Lawnbowls, Badminton, Golf and darts. The towns local football team, the Pinnaroo Supa Roos play in the Mallee Football League.
Pinnaroo also has a show and field days every year at the start of October. The Pinnaroo Show features dog trials, agricultural tents, competitions, horse events, keg tosses, animal judging and fireworks. The show attracts over 10,000 people every year. Another event Pinnaroo hosts is the Pinnaroo SpudFest. The SpudFest features a black tie dinner, stalls and games, entertainment, and Spud Wrestling.
The railway is not currently available for transport between the states, as the line from Tailem Bend was converted to standard gauge soon after the main Adelaide–Melbourne line was converted, but the line to Ouyen remains as broad gauge.