Appin is a town on the south-west fringe of Sydney in the Macarthur Region in Tharawal country near its boundary with Gandangara country, New South Wales, Australia in Wollondilly Shire. It is situated about 16 kilometres (9.9 mi) south of Campbelltown and 35 kilometres (22 mi) northwest of Wollongong.
Macarthur is a region in the Outer South-West part of the Greater Sydney area, in the state of New South Wales, Australia. The region includes the local government areas of the City of Campbelltown, the Camden Council and the Wollondilly Shire. It covers an area of 3,067 square kilometres and has a population of close to 310,000 residents.
The region is bounded at the north by Glenfield; at the south by Yanderra; at the east by the town of Appin; and at the west by the hamlet Nattai.