斯尔毛县是印度的一个县，位于该国北部，由喜马偕尔邦负责管辖，面积2,825平方公里，识字率为79.98%，2001年人口458,593，人口密度每平方公里162人。

Sirmaur is the most south-eastern district of Himachal Pradesh, India. It is largely mountainous and rural, with 90% of its population living in villages. It includes the towns of Nahan (its capital), as well as the Shivalik Fossil Park at Suketi, where fossils over 85 million years old have been found.