The Kra Isthmus is the narrow landbridge which connects the Malay Peninsula with the mainland of Asia. The east part of the landbridge belongs to Thailand, the west part belongs to the Tanintharyi division of Myanmar. To the west of the Isthmus is the Andaman Sea, to the east is the Gulf of Thailand. Its narrowest part has a width of 44km.
As the Malay Peninsula enlarges the shipping routes around Asia significantly, already in 1677 a canal through the Kra Isthmus was suggested. The idea is still entertained by a few Thai politicians today, however the high costs as well as ecological problems make it unlikely to be realized in the near future.