It is about 20 kilometres southwest of Kadina and 19 kilometres south of the port town of Wallaroo. At the 2001 census, Moonta had a population of 3,068. There are several distinct localities or hamlets surrounding Moonta, including Yelta, North Yelta, Moonta Bay, Port Hughes and Simms Cove.
It is thought that the name "Moonta" is derived from Moontera, a (indigenous) Narungga tribe word meaning 'impenetrable scrub'.
Large and rich deposits of copper were discovered at Moonta in 1861 by shepherds from Walter Watson Hughes' sheep farm, now Wheal Hughes. The town was laid out in 1863 and a horse drawn tramway to Wallaroo was established in 1863. Through advertisement by the South Australian Government, Cornish miners arrived in Moonta soon afterward. The mines at Moonta proved to be the richest mines in the whole of South Australia by 1917, exceeding the total wealth created by all other mines since 1836, the year of establishment of South Australia. The population of Moonta in 1875 was 12,000. The initial copper mining operations ceased in 1923, but smaller-scale modern operations, recommenced in the area in the 1990s.
Moonta, the town centre, consists of old limestone miners' cottages and churches, giving the town a historical feel. There are several eateries in the town centre, as well as at Moonta Bay.
The nearby locations of Moonta Bay, Port Hughes and Sims Cove are on the foreshore and are rapidly developing. They are extremely popular locations for retirement. The beaches are wide with fine, white sand, and are popular with recreational anglers and sailboarders. The natural state of the coast has largely been retained.
Tourism is a significant local industry, focussing on the availability of beachside accommodation- including several caravan parks and a motel.
North Yelta is an old mining village just north of Moonta. Like Moonta, it has an historic ambience.
Moonta also contains the Wheal Hughes Tourist Mine at the site of Wheal Hughes, the Moonta Heritage Site, the Moonta School of Mines and a folk museum.
The popular three-day Kernewek Lowender Cornish festival is held every odd year in May in the Copper Triangle towns, where each of the three towns hosts the festival for one day.