Kalyan, a town of British India, in the Thana district of Bombay, situated 33 m. N.E. of Bombay city, where the two main lines of the Great Indian Peninsula railway diverge. Pop. (1901), 10,749. There is a considerable industry of rice-husking. Kalyan is known to have been the capital of a kingdom and a centre of sea-borne commerce in the early centuries of the Christian era. The oldest remains now existing are of Mahommedan times.