In the very beginning, there was only one category of Brahmins, later they were categorized on basis of their lands (areas) as Gaur and Dravid. Both of them have five subcategories in themselves (panchgaur and panchdravid). Later 120 categories of Brahmins were developed among them.
Sarswat, Kanyakubja, Gaur, Utkal and Maithil, these are five gaurs and dwelling towards north of Vindhyachal. Punjab is the land of Saraswats. Kanauj, Ayodhya, Agra up to Delhi is the land of Kanyakubjas. Bihar and Bengal are the land of Maithil. The land between Gandaki and Kaushiki rivers is known as Maithil land. The Utkal is in the other side of Vindhyachal.
There are five Dravid lands- Karnataka, Maharashtra,Tailang, Dravid and Gurjar.
Among Kanyakubj,a all Brahmins of this area were Kanyajubja except Chaubeys of Mathura (Mathur) & Magadh (Pandas of Gaya)
Lord Rama of Ayodhya had organized Ashwvamedha Yajna to get rid of Brahm-Hatya (Killing of a Brahmin-Ravana* who was a Brahmin by birth). Lord Rama invited all Brahmins of Aaryavart (who till then were only Kanyakubja). Most of the Brahmins did not think proper to attend this Yajna & accepting the Daan of from a person who is involved in a Brahm-Hatya. Therefore, they did not participated Ashwvamedha Yajna. But some of Brahmins went to Ayodhya & participated in Yajna & also accepted the gifts (Daan). These Brahmins were finally settled in Ayodhya which was situated on river Saryu & were later known as Saryupari Brahmins.
*Ravana,the wicked king ruled Lanka & was born to Brahmin rishi Vishrava and Kekasi who belongs to a Rakshas clan.