Fort St George is the name of the first British fortress in India, built in 1644 at the coastal city of Madras (modern city of Chennai.) The construction of the fort provided the impetus for further settlements and trading activity, in what was originally a barren land. Thus, it is only correct to say that the city evolved around the fortress.

The Company, which had entered India around 1600 for trading activities, had begun licensed trading at Surat, which was its initial bastion. However, to secure its trade lines and commercial interests in the spice trade, it felt the necessity of a port closer to the Malaccan Straits. It succeeded in purchasing a piece of coastal land, originally called Madraspattinam (Channapatnam - by a few accounts.), from a local chieftain, where it began construction of a harbour and a fort. The fort was completed on April 23rd, coinciding with St. George's Day, celebrated in honour of St. George, the patron saint of England. The fort, hence christened Fort St. George faced the sea and a few fishing villages, and soon became the hub of merchant activity. It gave birth to a new settlement area called George Town, which grew to envelop the villages and led to the formation of the city of Madras. It also helped establish British influence over the Carnatic region, and keep the kings of Arcot and Srirangapatna, as well as the French forces based at Pondichery, at bay.

Today, the Fort serves as the administrative headquarters for the legislative assembly of Tamil Nadu state, and still houses a garrison for troops in transit to various locations at South India and the Andamans.

Fort St. George was also the name of the military fort built by the British in Bombay around the Casa da Orta, the old castle or keep of the Ortas, the Jewish tenants of the Portuguese king. This fort was later extended and then finally demolished, although a part of its walls remains, where the St. George Hospital now exists.