Kusha (Sanskrit: कुश, romanized: Kuśa) and his twin brother Lava were the children of Rama and Sita. Their story is recounted in the Hindu epic, the Ramayana. Hindu traditions claim he ruled the entire region of Kashmir, Indus River and Hindu Kush as frontier lands of India known as Hindu Kush Kshetra and founded the city of Kashmir in the valley and Kasur with Lavapuri of lava in base lands, though local lore contends Kasur was founded in 1525 by Pashtun migrants. His brother Lava is traditionally believed to have founded Lavapuri (current day city of Lahore).
The imperial line that ruled Kingdom of Benares-Kashi and the Maurya Empire, which ruled South Asia from 320 to 185 BCE, claimed descent from Kusha. Kusha is said to be a Raghuvamshi Ikshvaku Suryavamshi.
According to the Ramayana, a pregnant queen Sita leaves the kingdom of Ayodhya in revolt when the King, Lord Rama, asks her to prove her chastity to the citizens of the kingdom to prove wrong the allegation about her by a citizen of his kingdom. She then took refuge in the ashram of the sage Valmiki located on the banks of the Tamsa River. Sita gave birth to twin sons, Lava and Kusha, at the ashram and were educated and trained in military skills under the tutelage of Sage Valmiki. They also learned the story of Rama.
During an Ashvamedha Yajna held by Rama, Sage Valmiki along with Lava and Kusha, attended with Sita in disguise.
Lava and Kusha chanted the Ramayana in the presence of Rama and a vast audience. When Lava and Kusha recited about Sita's exile, Rama became grief-stricken and Valmiki produced Sita. Sita, struck with embarrassment and grief, called upon the earth, her mother (Bhūmi), to receive her and as the ground opened, she vanished into it. Rama then learnt that Lava and Kusha were his children.
In some versions, Lava and Kusha capture the horse of the sacrifice and defeat Rama's brothers and their army and when Rama came to fight with them. Sita intervened and unites father and sons.
Lava and Kusha became rulers after their father Rama and founded the cities of Lavapuri (modern day Lahore) and Kusha (Kasur) respectively.
Kushavati was a city in Kosala Kingdom as related in the epic Ramayana. The king of Kosala, Rama, installed his son Lava at Shravasti and Kusha at Kushavati.