Shahjahanpur, city in northern India, in central Uttar Pradesh. Shahjahanpur is located in the Rohilkhand region of the middle Gangetic Plain. Set in the heart of a sugarcane-producing region, the city has several sugar refineries. Other industries include chemical production and carpet weaving. Shahjahanpur is an important trade center. A major rail line and national highways connect the city with Kolkata, Delhi, and Lucknow. The nearest airport is in Lucknow. A cantonment (permanent military installation) lies within Shahjahanpur's urban area. The city was founded in 1647 during the reign of Mughal emperor Shah Jahan, whose name it bears. Population (1991) 237,713.