The most sacred and eastern source of the Sarasvatī is said to be Adi-Badri Kunda north of Katgadh [Kathgarh], while the latter is still remembered to be the place where the sacred stream came out of the hills.
Source, in full
Alexander Cunningham, See Bhargava, M.L., Geography of Rgvedic India, , p. 71, with reference to Archaeological Survey of India Report, vol. XIV, p. 75. quoted from Danino, M. (2010). The lost river : on the trail of the Sarasvatī. Penguin Books India.