This structure for containing warehouses and officers mess on the ground floor and above them the exchange together with a brokers office a committee room for the managers and a public coffee room was raised from the profit on the lottery in about 1795 AD.
The long hall was used as an exchange but also served for public meetings lottery drawings and occasionally for entertainment. The apartments of the ground floor were employed as auction rooms the subscription library and for the Madras bank since 1861 AD. The edifice had been the officers mess of the British regiment quartered at Fort St. George. It now houses the fort museum.
This colonial period museum at Fort. St. George was organized in 1948. There are 10 galleries including a temporary exhibition gallery spread in three floors. At the entrance, the information centre, ticket counter and a help desk for physically challenged visitors with facilities like touch screen , audio guide, Braille brochure, wheel chair etc are made available.
An open air kids gallery is in the rampart garden in front of the main entrance with a life size cannon model along with its working mechanism and a life size talking cannon model where the children are allowed to touch and learn.
- The arms gallery houses the British period weapons like petard, pistols, mortars, muzzle loading guns etc.
- The medal gallery houses the service medals, commemorative medals and medallions.
- The textile gallery houses the uniforms and regimental colours.
- The porcelain gallery has collection of the English, French and local rulers like the Nawabs.
- The fort St. George gallery houses model of the then fort, church objects and records etc.
- The statue gallery has the statues of the British personalities.
- The painting gallery houses mainly the portraits of British royals and the local Indian rulers.
- The coin gallery has a rich coin collection of all colonial powers and native rulers.
- The collection of prints by Thomas and William Danniels are exhibited in this floor
- A temporary exhibition gallery is for exhibiting antiquities from storage on rotation basis
- The air conditioned conference hall is being used for seminars and workshops related to museum activities.
- The first flag hoisted in Fort. St. George on 15th August 1947 is displayed here.
- The medals, stamps and other information related to Indian Independence are also displayed.
- In the freedom movement gallery the details of freedom fighters of Tamil Nadu is provided.
A small library with books related to freedom movement in India is available for the visitors.