Udapānatīrtha (Udapanatirtha)is an ancient site of pilgrimage on the bank of the river Sarasvatī (Saraswati). Trita, the Veda-knowing youngest son of sage Gautama, drank the juice of a vine hanging inside a well located in this place, imagining it to be Somarasa. So this site is called Udapāna. During his pilgrimage Valarāma (Valarama) visited this place. The river Sarasvatī probably flows here as antaḥsalilā (antahsalila, with a hidden flow underground). Seeing the moisture of the soil and the greenness of the vegetation growing there, Valarāma felt the presence of the river in Udapānatīrtha —
snigdhatvādoṣadhīnāñca bhūmeśca janamejaya
jānanti siddhā rājendra naṣṭāmapi sarasvatīm.

This Udapāna tīrtha is close to Vinaśna tīrtha.

Ekata , Dvita (Dwita) and Trita were the three sons of Sage Gautama brothers. Trita excelled in the work of a piest and the knowledge of Veda. He was well-respected, and so his brothers became jealous of him. One day, Ekata and Dvita planned that along with Trita, they will collect the cattles from all their yajamānas (yajamana; those who get yajñas performed by the priest). When at night, Ekata and his two brothers were returning by the banks of the river Sarasvatī (Saraswati), leading the cattles, they saw a tiger at some distance, blocking their way. There was also a big well nearby. Seeing the tiger, Ekata and Dvita fled in fear. But Trita, retreating backwards in fear, fell into the well. He started yelling from that well. Even hearing his cries for help, Ekata and Dvita left the place, in fear of the tiger and out of their possessiveness for the cattles. Trita then started performing a yajña, imagining the water inside the well as ghee for yajña (yajna; Vedic ritual). Hearing his chant of Vedic mantra (hymn) gods came down from the heaven to claim their share of the yajña. Finally, they rescued Trita from the well. The well where Trita fell down, became sacred, by the grace of gods. Taking a bath here, one may attain the status of a yājñik. When the well got filled with the water of Sarasvatī, Trita came out , pushed by the upward pressure of water. In course of time, this well and the adjacent area came to be known as Udapāna tīrtha.
[See Ekata, Dvita and Sarasvatī, Vinaśana]
According to Padmapurāṇa (Padmapurana), this place is highly suitable for Aśvamedha yajña (Aswamedha yajna). King Janaka had an well digged in this place. Sage Trita probably fell in that well.