A single district in 1965, two districts after statehood: how Goa was put together
Background
The South Goa district administration's own account of the territory's history begins in 1510: the Portuguese established a colony in Goa in 1510 and expanded the colony to its present boundaries during the 17th and 18th centuries. Goa was annexed by India on 19 December 1961. Goa and two other former Portuguese enclaves became the union territory of Goa, Daman and Diu, and Goa was organised into a single district in 1965. On 30 May 1987 Goa attained statehood, while Daman and Diu became a separate union territory, and Goa was reorganised into two districts, North Goa and South Goa. The two-district structure dating from 1987 is still the basis of the state's revenue administration.
In plain words
Enclave Enclave — A small territory held by one power but surrounded by the land of another.
Union territory Union territory — A part of India administered by the Union government rather than by a state government.
Annexation Annexation — The formal taking of a territory into the sovereignty of a state.