The Chennai Metropolitan Development Authority (CMDA), formerly known as the Madras Metropolitan Development Authority (MMDA), is the nodal planning agency of Chennai in the Indian state of Tamil Nadu.

The CMDA administers the Chennai Metropolitan Region, spread over an area of 5,904 km2 (2,280 sq mi) and covers the districts of Chennai, Thiruvallur, Chengalpattu, Ranipet and Kancheepuram.

The CMDA was constituted as an ad hoc body in 1972 under the Tamil Nadu Town and Country Planning Act 1971.

It was formed as the nodal Town planning authority for the city of Madras (now Chennai) and its suburbs and became a statutory body in 1974.

[2] The CMA falls in five Districts of the Tamil Nadu State viz.