Dadra and Nagar Haveli (Marathi: , , Portuguese: Dadrá e Nagar-Aveli) is a Union Territory in western India. Nagar Haveli is wedged between Maharashtra and Gujarat, whereas Dadra is a enclave 1 km NW surrounded by Gujarat. The shared capital is Silvassa. The larger part spans a large, roughly c-shaped area 12–30 kilometres up-river from the city of Daman on the coast, at the centre of which, and thus outside the territory, is the Madhuban reservoir.
Dadra and Nagar Haveli (DNH) are in the middle of the quite undulating watershed of the Daman Ganga River, which after the reservoir flows through Nagar Haveli and later forms the short southern border of Dadra. The towns of Dadra and Silvassa lie on the north bank of the river. The Western Ghats range rises to the east, and the foothills of the range occupy the eastern portion of the district. While the territory is landlocked, the Arabian Sea lies just to the west in Gujarat.
These territories were earlier ruled by the Koli chiefs who were defeated by the Hindu kings of Jawhar and Ramnagar. The Marathas had conquered and annexed these territories to their kingdom.
To keep the British at bay and to enlist their support against the Moghuls, the Marathas, who had founded their own empire/kingdom made friends with the Portuguese and signed with them a treaty in 1779. Under this, the Maratha-Peshwa agreed that the Portuguese would be allowed to collect revenues from Dadra and Nagar Haveli which consisted of 72 villages (then known as parganas, now referred to as district places).
In return for security against the two large empires, the main extent of the treaty's concessions to the Portuguese were that they would only collect revenue in compensation for their loss of a warship, Santana, which had earlier been captured by the Marathas but not surrendered to the Portuguese in spite of their many entreaties.
It was annexed by India from Portugal on 2 August 1954. The people of the territory established free administration of Dadra and Nagar Haveli, which was finally merged into the Union of India in 1961.