The name Darrang is thought to have originated from the Sanskrit word 'Dwaram' meaning 'Duar' or pass. The region was significant for its passes through which various hill tribes descended from the Himalayas. Other theories trace the name to 'Devaranga', meaning the playground of Devas.
The name Mangaldai is traced to Mangola Devi, daughter of Koch king Lakshminarayana. Archaeological finds, such as the bronze Vishnu icon from the 11th century, reflect the region's rich past. Various sites like Narikali, Tamreswar, and Bijulibari stand as evidence of ancient glory.
During this period, Darrang was a part of Koch Hajo under Raghudev. Conflicts with the Mughals and Ahoms marked this era, and later Darrang became a feudatory under Ahom king Pratap Singh. By the late 1700s, the Ahoms lost power, eventually leading to British control.
After the Treaty of Yandabu in 1826, Darrang came under British rule. In 1894, the district witnessed the Patharughat uprising, where many lost their lives protesting against British-imposed taxes, a significant moment in Assam's history.
Darrang became a district with its headquarters initially at Mangaldai in 1833. In 1983, Mangaldai was established as a separate district. The people of Darrang played a significant role in India's freedom struggle and continue to contribute to Assam's cultural heritage.