Sirsa (Hindi: ) is a city and a municipal council in Sirsa district in the Indian state of Haryana. It is a town in the westernmost region of the state, bordering Punjab and Rajasthan. Its history dates back to the time of Mahabharata.
At one time, the Sarasvati River flowed in this area. Sirsa is said to be one of the oldest places of North India and its ancient name was Sairishaka, which finds mention in Mahabharata, Panini's Ashatadhayayi and Divyavadan. In Mahabharata, Sairishaka is described as being taken by Nakula in his conquest of the western quarter. It must have been a flourishing city in the 5th century BC, as it has been mentioned by Panini. There are a number of legends about the origin of the name of the town. It seems to have been corrupted to Sirsats from its ancient name Sairishaka. According to local tradition, an unknown king named Saras founded the town in the 7th century AD and built a fort. The material remains of an ancient fort can still be seen in the South-East of the present town. It is about 5 km in circumference. According to another tradition, the name has its origin from the sacred river Sarasvati which one flowed near it. During medieval period, the town was known as Sarsuti. It has been mentioned as Sarsuti by a number of medieval historians. In ancient period, Sirsa was also known as Sirsapattan.