Bihu is by far the most important festival of Assam. While Rongali Bihu or Bohag Bihu, coinciding with the Assamese new year is the principal bihu, the harvest festival, known as the Bhogali Bihu or Magh Bihu is also equally important. There is a third bihu called the Kangali Bihu or Kati Bihu, which is solemnly observed to pray for a better crop.

The bihus are popular agriculture-based festivals, and are traced to the remote past. While Rongali Bihu is full of dances and songs and merriment, Bhogali Bihu is a festival of community feasts and bonfire.

During the modern times, Rangali Bihu has become a major urban festival, accompanied by competitive performance of folk songs, group dances, playing of drums and so on.

In Kamrup and Darrang districts, Bhatheli or Suari or Deul forms an important adjunct of the spring time bihu festival, and is accompanied by fairs too.