Ekapṛṣṭha (Ekaprishtha) is the name of a race or tribe, and the the place inhabited by that tribe, as mentioned in Bhiṣmaparva (Bhishmaparva) of Mahābhārata (Mahabharata). But alternative readings of the term ‘Ekapṛṣṭha’ can also be found. In some places, it is also referred to as ‘Naikapṛṣṭha’ (Naikaprishtha). In the catalogue of the names of the tribes and localities, described in Bhiṣmaparva, Ekapṛṣṭha is mentioned along with Pañcāla (Panchala)and Yugandhara ( ‘Dhurandhara’ in another reading), which suggests the geographical proximity between Ekapṛṣṭha and Yugandhara .
In Purāṇa (Purana; Mythological Scriptures), we find the mention of several north-eastern tribes such as Ekacaraṇa (Ekacharana), Ekanetra and the like. Due to similarity in nomenclature, Ekapṛṣṭha was possible related to thee tribes. It may also be noted that both Ekacaraṇa and Ekanetra were branches of the Kirāta(Kirata) tribe.
TIM (K.C. Mishra) p.85