Deorhi at Garhbanaili (Purnea) hosts the ruins of Kala Bhawan the ancient Darbar (Palace) of Raja Kalanand Singh, where his successor still lives.Kala Bhawan / Palace of Raja Kalanand Singh, Purnea
Raja Kalanand Singh is listed in the official directory of the Coronation Durbar of 1911 as one of those attending the ceremonies.
The name of the estate derives from a village Banaili in the then Purnia district of Bihar. Banaili Raj also known as Garhbanaili Raj was a zamindari estate based in the Indian state of Bihar. They were considered one of the ruling dynasties of the Mithila region. Rulers and holders of this estate were Maithil Brahmin.
The main centres of residences of Rajas of Banaili are Banaili, Ramnagar, Champanagar, Srinagar, Garh Banaili, and Sultanganj. Bhagalpur was the centre from where administration of the estate was carried out.