New States and Union Territories Created After 1956:

Maharashtra and Gujarat:

On 1 May 1960, by the Bombay Reorganization Act. the bilingual state of Bombay was divided into two separate states - Maharashtra for Marathi speaking people and Gujarat for Gujarati speaking people. Gujarat was established as the 15th state of the Indian Union.

Dadra and Nagar Haveli:

The Portuguese ruled this territory until its liberation in 1954. Subsequently, the administration was carried on till 1961 by an administtator chosen by the people themselves. It was converted into a union territory of India by the 10th Constitutional Amendment Act, 1961.

Goa, Daman and Diu:
India acquired these three territories from the Portuguese by means of a police action in 1961. They were constituted as a union territory by the 12th Constitutional Amendment Act, 1962. Later, in 1987, Goa was conferred a statehood. Consequently, Daman and Diu was made a separate union territory.

Puducherry:

Puducherry comprises the former French establishments in India known as Puducherry, Karaikal, Mahe and Yanam. The French handed over this territory to India in 1954. Subsequently, it was administered as an acquired territory, till 1962 when it was made a union territory by the 14th Constitutional Amendment Act.

Nagaland:

In 1963, the State of Nagaland was formed by taking the Naga Hills and Tuensang area out of the state of Assam. Before giving Nagaland the status of the 16th state of the Indian Union, it was placed under the control of governor of Assam in 1961.

Haryana, Chandigarh:

In 1966, the State of Punjab was divided to create Haryana, the 17th state of the Indian Union, and the union territory of Chandigarh.

Himachal Pradesh:

In 1971, the union territory of Himachal Pradesh was elevated to the status of a state as 18th state of the Indian Union.

Manipur, Tripura and Meghalaya:

In 1972, the two Union Territories of Manipur and Tripura and the Sub-State of Meghalaya got statehood and the two union territories of Mizoram and Arunachal Pradesh (originally known as North- East Frontier Agency-NEPA) came into being. With this, the number of states of the Indian Union increased to 21 (Manipur 19th, Tripura 20th and Meghalaya 21st).

Sikkim:

Till 1947, Sikkim was an Indian princely state ruled by Chogyal. In 1947, after indepenence, Sikkim became a protectorate of India, whereby the Indian Government assumed responsibility for its defence. In 1974, Sikkim expressed its desire for greater association with India. Accordingly, the 35th Constitutional Amendment Act (1974) was enacted by the parliament. This amendment introduced a new class of statehood under the constitution by conferring on Sikkim the status of an associate state of the Indian Union.

Mizoram, Arunachal Pradesh and Goa:

In 1987, three new States of Mizoram, Arunachal Pradesh and Goa came into being as the 23rd, 24th and 25th states of the Indian Union respectively.

Chhattisgarh, Uttarakhand and Jharkhand:

In 2000, three more new States of Chhattisgarh, Uttarakhand and Jharkhand were created out of the territories of Madhya Pradesh, Uttar Pradesh and Bihar respectively. These became the 26th, 27th and 28th states of the Indian Union respectively.