Odisha Day (Oriya: ଓଡ଼ିଶା ଦିବସ) also known as Utkala Dibasa is celebrated on 1st April in Odisha in the memory of the formation of the state as a separate province on 1st April 1936.  After losing its complete political identity in 1568 following the defeat and demise of the last Hindu king Mukunda Dev, efforts resulted into the formation of a politically separate state under British rule on linguistic basis on 1 April 1936.
The main revolution for this separate state was continued for three decades from the very day of formation of Utkal Sammilani that lead the foundation of a separate Odisha Province. The movement was more intensed with the leadership of Utkala Gouraba Madhusudan Das, Utkala mani Gopabandhu Das, Maharaja Krushna Chandra Gajapati, Pandita Nilakantha Das, Fakir Mohan Senapati, Gangadhar Meher, Basudeba Sudhaladeba, Radhanath Ray, Bhubanananda Das, A. P. Patro and many others with the support of the public. The newly formed Odisha consisted of six districts namely Cutack, Puri, Baleswar, Sambalpur, Koraput and Ganjam having its capital at Cuttack. John Austin Hubback took oath of office and became the first Governor of Odisha Province.
- "Utkal Dibasa also called Odisha day is being celebrated on April 1st today". infocera.com. 2012. Retrieved 3 July 2012. "The Odisha province was formed on the basis of linguistic pattern of people in the area on April 1, 1936"
- "Poor water management has made Odisha victim of drought and floods". The Hindu. Retrieved 6 April 2006.
- Orissareview. April 2008. pp. 17-19
- Formation of Orissa as a Separate Province by Pareswar Sahoo. Orissareview. April 2006
- Orissa's new name is OdishaThe Times Of India