Ikshwakus were a mythical dynasty of rulers of ancient India, which branched out from the Solar Dynasty. They ruled from the Kosala Kingdom with Ayodhya as their capital. The two Indian epics, viz. Ramayana and Mahabharata have numerous mentions of this dynasty. The most famous among all the Ikshwaku kings was Raghava Rama, the son of Dasaratha. He is the central hero of the epic Ramayana. In Mahabharata, they were mentioned as one of the most prominent races (MBh 1:1). During the Rajasuya ceremony of Pandava king Yudhisthira, Ikshwakus along with Ailas were mentioned as the prominent Kshatriya races of the time. King Suvala is mentioned as an Ikshwaku king and a friend of Sindhu king Jayadratha (MBh 3:263). At 13:2 the founder of the race, viz. Ikshwaku, the Suryavanshi was mentioned as the son of the ancient patriarch Manu. Many kings like Aja and Trishanku were mentioned as Ikshwaku kings.
The following passage is from Mahabharat 14:4 describing the lineage of Ikshwakus
In the Krita age, Manu was the lord (of the Earth) wielding the scepter. His son was known by the name of Prasandhi. Prasandhi had a son named Kshupa and Kshupa’s son was that lord (of men), King Ikshwaku. He had many sons endowed with preeminent piety and all of them were made monarchs by King Ikshwaku. The eldest of them, Vinsa by name became the model of bowmen. Vinsa’s son was the auspicious Vivinsa. Vivinsa had five daughters and ten sons; all of them were powerful archers, reverential to the Brahmanas and truthful as well as gentle. The eldest brother, Khaninetra, oppressed all his brothers. Even after having conquered the entire kingdom, Khaninetra could not retain his supremacy; nor were the people pleased with him. And dethroning him, they invested his son Suvarcha with the rights of sovereignty. He vanquished all the kings living along the borders of his dominions and from this circumstance he hath been celebrated as Karandhama. His son, (the first) Karandhama who was born at the beginning of the Treta age, equaled Indra himself and was endowed with grace and was invincible even at the hands of the immortals. At that time, all the kings were under his control; and alike by virtue of his wealth and his prowess, he became their emperor. In short, the righteous king Avikshit by name, became like Indra himself in heroism. He performed hundreds of Aswamedha sacrifices, and the potent and learned Angira himself served as his priest. His son surpassed his sire in the possession of good qualities. Named Marutta, that lord of kings was righteous and of great renown, and possessed the might of ten thousand elephants. That virtuous monarch, coming to Mount Meru on the northern side of Himalayas, caused thousands of shining golden vessels to be forged and there on a huge golden hill he performed the rites.