A former Portuguese territory in China. It lies on the western side of the Pearl River Delta, bordering Guangdong province in the north and facing the South China Sea in the east and south. Stamps were first issued in 1884.
Since 1999 Macao is now one of the two special administrative regions of the People's Republic of China, the other being Hong Kong.
Official website of Correios de Macau.
Wikipedia page providing an brief overview of Macao stamps and postal history.