The Tamil Nadu State Department of Archaeology (TNSDA) is a Governmental Research Organization (institution) of the Government of Tamil Nadu, headquartered in Chennai. It was established in 1961 as an official research department with the primary objective of conserving and preserving ancient monuments and conducting excavations at historical sites within the state. The creation of the TNSDA addressed the need for a dedicated state body to research and protect Tamil Nadu's rich cultural heritage.
The Department's mechanism involves several key activities: it conducts archaeological excavations, having completed work at over 40 sites since 1968. Its functions also include Epigraphy, which is the copying and deciphering of stone inscriptions, and the chemical preservation of art objects, a process supported by a laboratory operating since 1980. The TNSDA also manages 14 site museums and is responsible for the registration of antiquities.
The TNSDA's work is governed by the state's Tamil Nadu Ancient Monuments and Historical and Archaeological Sites and Remains Act, 1966 (Tamil Nadu Act 25 of 1966) and Rules, 1971. It connects to the central government's Archaeological Survey of India (ASI), as it must obtain ASI's permission for excavations under the Ancient Monuments and Archaeological Sites and Remains Rules, 1959. Recently, in March 2026, the ASI granted approval for the TNSDA to conduct the 11th phase of the significant Keeladi excavation, along with seven other sites, following a budget allocation of ₹7 crore for archaeological research in 2025-26. The department also runs the Tamil Nadu Institute of Archaeology and Museology.