Wikipedia
Ahichchhatra (or Ahi-Kshetra) was the ancient capital of Northern Panchala, a northern Indian kingdom mentioned in Mahabharata. The remains of this city has been discovered in Ramnagar a village situated in the Aonla Tehseel of Bareilly District in Uttar Pradesh, India.The excavations have brought to life a brick fortification and continuity of occupation from a period before 600 BCE to 1100 CE. During the first excavations in 1940–44, the Painted Gray Ware pottery were found at the earliest level. Ruins of this city could be identified from the remote sensing imagery of IRS (Indian Remote Sensing) satellites. The ruins reveals that the city had a triangular shape. Recent excavations in Ahichchhatra showed it was first inhabited by the middle of the second millennium BC with Ochre Coloured Pottery culture people, followed by Black and Red Ware culture. Around 1000 BC, it reached at least 40 hectares of area, making it one of the largest Painted Grey Ware culture sites. The city was alive up to end of Kurukshetra war. Near the Ahichchhatra 2 km west there is also a big pond at the time of Mahabharta in the village of jagannathpur and today the people bath in that pond this pond is made by the pandavs at the time of banvas.
The territory under Ahichchhatra was formerly under the Panchala king Drupada. Later it was taken over by Drona, after a war, in which Drupada was defeated by Drona's disciple Arjuna. Ashwatthama, the son of Drona, was given the responsibility of ruling the territory of Northern Panchala from Ahichchhatra. Ashwatthama probably ruled the kingdom being subordinate to the rulers of Hastinapura.
The word Ahi means snake or Naga in Sanskrit. Nagas were a group of ancient people who worshiped serpents. The word khsetra means region in Sanskrit. This implies that Ahi-kshetra was a region of Nagas. This could mean that the region was populated originally by Nagas, Nairs, Havyakas Bunts of Kerala and Tulu Nadu who claim Kshatriya descent from the nagas as well as Namputhiri and Tuluva Brahmins(Hindu philosophers Adi Shankara and Madhvacharya belonging to these communities) trace their origins to this place.