- Madras is a city in the state of Tamil Nadu, India. It is also known as Chennai, and is the capital of the state. Madras/Chennai is the fourth-largest city in India and has a population of over 8 million people. It is a major cultural, economic, and educational hub in South India. The city is known for its beaches, temples, historic landmarks, and vibrant arts and music scene. It is also home to several IT and automobile industries, making it an important economic center in the country.