Another region that did not initially join the union was Hyderabad. The Nizam, a muslim ruler had a large Hindu population but still he was thinking of staying independent. A year was given to the Nizam to make a decision by the Indian Administration. By 1948, there was no decision and the Indian troops rolled into Hyderabad and the Nizam signed the dotted line.
This series is part of “15 days of Independence”:http://varnam.nationalinterest.in/archives/cat_indian_independence.html