The word Havyaka was transcended from words Havyaga or Haveega which means the one who performs Havana(Havya) and Homa(Gavya), since the very purpose of Havyaka Brahmins was to perform the royal rituals and the related functions of the empirical government. In fact, the name “Haiga” persists in Havyaka lexicon.The word Havyaka might also be derived from the place named Haigunda. That region of Karnataka which has been inhabited by Havyakas from ancient times is also called Parashuramakshethra, Gorastradesha, Gokarnamandala.
Exact facts about Havyaka’s origin are hard to come by since there are very little research available. Historically, it is believed that Havyakas are the first of the Brahmin kind to descend to the present day Karnataka around 3rd century ACE, followed by other sects like Shivalli, Smartha etc., who arrived much later, around 7th century ACE.  However, the scientific school of thought places the date of Havyaka’s immigration back to about 1300 years ago. The Brahmin king Mayooravarma was instrumental in bringing the first Havyaka families. It is believed that Kadambas brought many Havyakas in to perform the royal rituals and the related functions of the empirical government from a place called Ahichchathra in the state of Uttar Pradesh. Thus the first few families were settled in Banavasi, the capital of the Kadambas and the place adored by Pampa. King Mayooravarma’s act of inviting Havyakas to Banavasi has been inscribed on a stone stab(Shilashasana) from the period of the Kadambas, which now lies near the village of Varadahalli in Sagar Taluk of Shimoga district.
The descendants and associates of Parshuram are called Bhumihar Brahmins in Eastern U.P. and Bihar, Goud Brahmins in U.P. and Rajasthan, Chitpawan Brahmins in Maharashtra, Anavil Brahmins in Gujarat, Havyak Brahmins in Karnataka, Namboothiri Brahmins in Kerela and Mohyals in the Punjab region. Their variants are found with different names all across the Indian sub-continent. They have same Aryan looks, customs and practices.
– source Wikipedia encyclopedia