The distance between Trashigang and Samdrup Jongkhar is 180 km and takes 6 to 7 hours drive. The highway was constructed in 1960s and aided in opening up  eastern Bhutan to the outside world, resulting in increased trade with neighboring Indian state of Assam. Samdrup Jongkhar is the entry and exit points to and from the airport from Guwahati (India), the capital of Assam, which is 101 km from Samdrup Jongkhar.