SIRMUR, or Sarmor (also called Nahan, after the chief town), a native state of India, within the Punjab. It occupies the lower ranges of the Himalaya, between Simla and Mussoorie. Area 1198 sq. m. The state is bounded on the N. by the hill states of Balsan and Jubbal, on the E. by the British district of Dehra Dun, from which it is separated by the rivers Tons and Jumna, on the S.W. by Umballa district, and on the N.W. by the states of Patiala and Keonthal. Except a very small tract about Nahan, the chief town and residence of the raja, on the south-western extremity, where a few streams rise and flow south-westward to the Saraswati and Ghaggar rivers, the whole of Sirmur lies in the basin of the Jumna, which receives from this tract the Giri and its feeders the Jalal and the Palur. The Tons, the great western arm of the stream called lower down the Jumna, flows along the eastern boundary of Sirmur, and on the right side receives from it the two small streams Minus and Nairai. The surface generally declines in elevation from north to south; the chief elevations on the northern frontier (Chor peak and station) are about 12,000 ft. above the sea. The valley of the Khiarda Dun, which forms the southern part of the state, is bounded on the S. by the Siwalik range, the hills of which are of recent formation and abound in fossil remains of large vertebrate animals. Though the rocks of Sirmur consist of formations usually metalliferous, the yield of mineral wealth is small. The forests are very dense, so much so that the sportsman finds difficulty in making his way through them in search of deer and other game, with which they abound. The climate of Sirmur varies with the elevation; the northern extremity has very little rain; but large and excellent crops are everywhere to be obtained by irrigation. The population in 1901 was 135,687, showing an increase of 9% in the decade. Estimated gross revenue, £40,000. The chief, whose title is raja, is a Rajput of high lineage. The raja Shamsher Perkash, G.C.S.I., who died in 1898, ruled with remarkable ability and success. A younger son commanded the Imperial Service sappers in the Tirah campaign of 1896-97, and was rewarded with the rank of honorary captain in the Indian army and the distinction of C.I.E. Attempts have been made to establish an iron foundry, and to develop mines of slate and mica.
The town of Nahan is situated about 40 m. S. of Simla, 3057 ft. above the sea-level. The palace of the raja and several other houses are built of stone in European style. It had a population in 1901 of 6256.