Pancha-Gauda and Pancha-Dravida are two chief divisions of Brahmins, as per the śloka from Rājatarangini of Kalhaṇa / Kalhana:
कर्णाटकाश्च तैलंगा द्राविडा महाराष्ट्रकाः , गुर्जराश्चेति पञ्चैव द्राविडा विन्ध्यदक्षिणे ||
सारस्वताः कान्यकुब्जा गौडा उत्कलमैथिलाः, पञ्चगौडा इति ख्याता विन्ध्स्योत्तरवासिनः ||
Meaning :(The-) Karnātakas, Tailangas, Dravidas, Mahārāshtrakās and Gurjaras; these five(-types who-) live south of Vindhya (- mountains) are (called-) "five Dravidas" (- brahmins); (whereas-) Sārasvatas, Kanyakubja Brahmins, Gauḍa brahmins, Utkala Brahmins, and Maithil Brahmins, who live north of Vindhya (- mountains) are known as "five Gaudas" (-brahmins)[1].[2][3].
The differentiation of brahmin community is mentioned in a Sanskrit text Brāhmaṇotpatti-mārtaṇḍa [4] :
Meaning : There was one caste of Brahmin in the beginning of Creation, but due to difference in country (of residence) it got bifurfated into two, namely Gauda and Dravida (i.e., Panch-Gauda and Panch-Dravida), which was again differentiated into ten (five Panchgaudas and five Panchdravida sub-castes).
Panch-Gauda still include a major portion of all Brahmin communities in North India [5], barring a few migrant Brahmin communities like Shakadvipi [6]. Panch-Gauda includes many branches all of which come under Brahmin communities.