athadiksata raja tu
brahmavarte manoh ksetre
yatra praci sarasvati
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The great sage Maitreya continued: My dear Vidura, King Prthu initiated the performance of one hundred horse sacrifices at the spot where the river Sarasvati flows towards the east. This piece of land is known as Brahmavarta, and it was controlled by Svayambhuva Manu.