Sylhet Division (Bengali: সিলেট বিভাগ) is the northeastern division of Bangladesh. It is bordered by the Indian states of Meghalaya, Assam and Tripura to the north, east and south respectively, and by the Bangladeshi divisions of Chittagong to the southwest and Dhaka and Mymensingh to the west. Prior to 1947, it included the subdivision of Karimganj (presently in Barak Valley, India). However, Karimganj (including the thanas of Badarpur, Patharkandi and Ratabari) was inexplicably severed from Sylhet by the Radcliffe Boundary Commission. According to Niharranjan Ray, it was partly due to a plea from a delegation led by Abdul Matlib Mazumdar.
The Sylhet Division is named after its headquarters, the city of Sylhet. Sylhet is the anglicization of শিলহট (Śilhôṭ), one of the archaic native names for the city. The local name is generally thought to be directly derived from শ্রীহট্ট (Śrīhaṭṭa), the Sanskrit name of the city, which was also commonly used in literary Bengali up until the 20th-century.
References: Wikipedia