Raghu was a ruler of the Ikshvaku dynasty. According to the Raghuvamsha, he was born to king Dilīpa and his queen Sudakshina. His name in Sanskrit means the fast one, deriving from Raghu's chariot-driving abilities. So celebrated were the exploits of Raghu, that his dynasty itself came to be known as the Raghuvamsha or the Raghukula after him. The history of his dynasty is elaborated upon by Kalidasa in his Raghuvamsha.
A number of Puranas, which include the Vishnu Purana, the Vayu Purana, the Linga Purana, mention Dirghabahu as the son of Dilīpa and Raghu as the son of Dirghabahu. But the Harivamsha, the Brahma Purana and the Shiva Purana mention Raghu as son of Dilīpa and Dirghavahu as his epithet. The lineage described in the Raghuvamsha mention Dilīpa as the father of Raghu. According to most of the Puranas, as well as Kalidasa, Raghu was succeeded by his son Aja, who was the father of Dasharatha, the father of Rama, Lakshmana, Bharata and Shatrughna.
Raghu's father, Dilīpa, was a very pious king, and performed as many as 100 yajnas or Vedic pure rituals. Until he did so, only Indra, king of the Gods, had earned that distinction. In a bid to prevent Dilipa from equaling his record, Indra placed many hurdles in the path of the successful completion of the 100th sacrifice, but Raghu was able to prevail over the forces of Indra himself, and the Vedic rituals was completed successfully.