List of Regional Festivals in India

Andhra Pradesh :
Sankranthi (this is the biggest festival in Andhra Pradesh)
Bonalu
Tyagaraja Festival
Brahmotsavam
Ugadi (New Year)
Vaikunta Ekadashi

Assam and Manippur :
Bhogali bihu
Bohag Bihu (or Rangali Bihu)
Kati Bihu (or Kangali Bihu)
Spring Festival of Kanyak Nagas
Manipur Ras Lila Festival

Bengal :
Gangasagar Mela
Ramakrishna Utsav
Dol Purnima
Naba Barsha
Dussera (famous in Bengal)

Bihar :
Chhath
Sarhul
Karam

Delhi :
Christian Mela
Sair-i-Gulfaroshan (Phool Walon Ki Sair)
Urs at Hazrat Nizam ud din Apulia

Goa :
Zatra at Cansaulim
Feast of St. Francis Xavier
Carnival

Himachal Pradesh :
Minjar Mela
Jwalamukhi Fair

Jharkhand :
Sarhul
Karam
Jawa
Maker
Bhagta Parab
Bandna
Dussehra
Chhat Puja
Diwali

Karnataka :
Makara Sankranthi,
Ugadi
Karaga
Feast of St. Philomena
Dasahra
Urs of Hazrat Khwaja Bande Nawaz Chisti
Mahamastakabhisheka (held once every 12 years in veneration of Gomateswara Bahubali at Sravanabelagola)

Kashmir :
Nav Warih
Sont
Vaisakhi
Jeth Ashtami
Mela at hemis Gampa
Har Navami
Piligrimage to Amarhnath Cave (Chhari Festival)
Urs at Shah Hamadan
Kichri Amavasya

Kerala :
Thye Pangal
Vishu
Poorum
Onam

Maharashtra and Gujarat :
Gudi Padva
Dev Divali
Navratri

Orissa :
Rathyatra (at Puri)

Punjab and Haryana :
Lahri
Tikka

Rajasthan and Madhya Pradesh :
Gangaru
Teej
Pushkar Fair
Urs at Ajmer
Sharif

Tamilnadu :
Pongal
Panguni Uthiram
Puthandu (Tamil New Year)
Madurai River Festival
Kaveri River Festival
Festival at Velanganni
Karthika Festival
Vaikunta Ekadashi

Tripura :
Karachi Puja
Tripureshwari temple festival

Uttar Pradesh :
Brahmostav
Ram Navami
Sravana Festival
Ban Yatra
Kans Ka Mela