Asahan Regency is a regency in North Sumatra, Indonesia. Following the creation of the new Batubara Regency, the regency now covers an area of 3,702.7 square kilometres; it had a population of 668,272 according to the 2010 census and 769,960 at the 2020 Census. Its administrative centre is now at Kisaran. The Regency surrounds but now does not include the city of Tanjungbalai which was formerly its capital. The Asahan Sultanate was located in the region.