The District of Tiruvarur was carved out as a separate district by detaching Valangaiman Taluk from Thanjavur District and Thiruvarur, Nannilam, Kudavasal, Needamangalam, Mannargudi , Thirutturaippundi Taluks from Nagappatinam District on 01.01.1997. There are 2 Revenue Divisions, 7 Taluks, 10 Blocks, 4 Municipalties and 7 Town Panchayats in Thiruvarur District. Thiru M. R. Mohan IAS was the first District Collector of Thiruvarur District.
Thanjavur attained prominence under the Chola rulers who were paramount in South India during the 9th to 12th centuries. They were excellent rulers and mighty builders. Many examples are found in the district which bears testimony to this. Many of these temples reflect the geniusness and architectural proficiency in sculpture, painting and wood-carving.
The administration of Thanjavur (Tiruvarur) was given over to English fully under the Treaty of 1799. The ruler of Thanjavur was allowed to retain the fort of Thanjavur with very limited powers. When the ruler died in 1841, without heir, the Thanjavur fort was also annexed by the British. Thanjavur remained under the British rule until 1947 when India attained freedom.