The first sugar mill in India was established in Bihar. Let's explore the details behind this answer.

1. The History of Sugar Mills in India:
- Sugar mills are industrial facilities that process sugar cane to produce sugar. The history of sugar mills in India dates back to ancient times when the extraction of sugar from sugarcane was first discovered.
- The sugarcane cultivation and sugar production techniques were introduced to India by the Arabs in the 8th century during their trade expeditions.
- Over the centuries, the cultivation of sugarcane and the establishment of sugar mills spread across various regions of India.

2. The Establishment of the First Sugar Mill:
- The first sugar mill in India was established in Bihar. Bihar is a state located in the eastern part of India.
- The establishment of the first sugar mill in Bihar can be attributed to the efforts of the British colonial rulers who recognized the agricultural potential of the region.
- The fertile Gangetic plains of Bihar provided a suitable environment for the cultivation of sugarcane, making it an ideal location for the establishment of a sugar mill.

3. Bihar's Importance in Sugar Production:
- Bihar has a significant history in sugar production, with several sugar mills operating in the state.
- The climatic conditions, fertile soil, and availability of water resources in Bihar make it conducive for sugarcane cultivation.
- The state has a strong agricultural base and is one of the leading producers of sugarcane in India.
- The establishment of the first sugar mill in Bihar marked the beginning of a flourishing sugar industry in the state.

In conclusion, the first sugar mill in India was established in Bihar. The state's favorable agricultural conditions and its importance in sugarcane cultivation contributed to the establishment of the mill. Over time, Bihar has become a prominent region for sugar production in India.