Siliguri is a city in the Indian state of West Bengal. It is located in the Siliguri Corridor or Chicken's Neck � a very narrow strip of land linking mainland India to its north eastern states. It is also the transit point for air, road and rail traffic to the neighboring countries of Nepal, Bhutan and Bangladesh. The town hosts over 500,000 domestic and 15,000 foreign visitors annually. It is the commercial nerve center of North Bengal. Siliguri is situated in Darjeeling district, and though it is the district's largest city, the district headquarters is located at Darjeeling. Siliguri is a unique city as 15 out of 47 wards of Siliguri Municipal Corporation falls in neighbouring Jalpaiguri district. The Indian army, Border Security Force (BSF), Central Reserve Police Force (CRPF), Shashatra Seema Bal (SSB) and the Assam Rifles have bases around the town. The Bagdogra Airport is located within the Indian Air Force (IAF) cantonment area. Siliguri has an Indian Oil Corporation Ltd. (IOC) oil depot near the southern edge of the town. Siliguri is the fourth largest city of West Bengal after Kolkata, Asansol and Durgapur.