Often rivers formed the boundaries of two neighboring kingdoms, as was the case between the northern and southern Panchala and between the western (Pandava's Kingdom) and eastern (Kaurava's Kingdom) Kuru. Sometimes, large forests, which were larger than the kingdoms themselves, formed their boundaries as was the case of the Naimisha Forest between Panchala and Kosala kingdoms. Mountain ranges like Himalaya, Vindhya and Sahya also formed their boundaries.