Mariana is the oldest city in the state of Minas Gerais, Brazil. It is a tourist city, founded on July 16, 1696, and retains the characteristics of a baroque city, with its churches, buildings and museums. It was the first capital of Minas Gerais.

Other historical cities in Minas Gerais are Ouro Preto, São João del-Rei, Diamantina, Tiradentes, Congonhas and Sabará.

It has an area of 1,194.208 square kilometres (461.086 sq mi).

The municipality contains a very small part of the 31,270 hectares (77,300 acres) of Serra do Gandarela National Park, created in 2014.

In 2015, it suffered a major dam disaster.