Surasena (or Sourasena) (Sanskrit: शूरसेन, Śūrasena) was an ancient Indian region corresponding to the present-day Braj region in Uttar Pradesh. According to the Buddhist text Anguttara Nikaya, it is mentioned in the Ramayana as an earlier Janapada state from at least 1000 BCE. Surasena was one of the solasa (sixteen) Mahajanapadas (powerful realms) in the 7th century BCE. The ancient Greek writers refer to the region as Sourasenoi and mention its capital as Methora.
There are several traditions regarding the etymology of its name. According to one tradition, it was derived from a famed Yadava king, Surasena, while others see it as an extension of Surabhir (Abhira) or Ahir. It was the sacred land of Lord Krishna in which he was born, raised, and ruled.
The Mahabharata and the Puranas refer to the rulers of the Mathura region as the Yadus or Yadavas, divided into a number of septs, which include the Vrishnis. The Buddhist texts refer to Avantiputta, the king of the Surasenas in the time of Maha Kachchana, one of the chief disciples of Gautama Buddha, who spread Buddhism in the Mathura region.
Its capital, Mathura, was situated on the bank of the river Yamuna, presently a sacred place for the Hindus. The ancient Greek writers mention another city, named Cleisobora, in this region.