Thailand, formerly Siam, officially kingdom Thailand, kingdom in southeast Asia. The territory borders in the north and west on Myanmar (Birma), in the northeast on Laos, in the southeast on Cambodia and the golf of Thailand (Siam), in the south on Malaysia and in the southwest on the Andaman sea and Myanmar. The total area of Thailand is totals 513.115 square kilometre, approximately the same large France. Bangkok is the capital and the largest city of the kingdom.