Phahonyothin Road

Phahonyothin Road (, , ) or Highway 1 is a major road in Bangkok and one of the four primary highways in Thailand, which include Mittraphap Road (Highway 2), Sukhumvit Road (Highway 3), and Phet Kasem Road (Highway 4). It begins at Victory Monument in Bangkok and runs north to the Burmese border, with a total length of .
History.
Phahonyothin Road was originally called Prachathipatai Road (, "Thanon Prachathipatai", literally "Democracy Road"), and reached just to Don Mueang. In 1938, Field Marshal Plaek Phibunsongkhram had the road extended from Don Mueang, through Bang Pa-In, Ayutthaya, Saraburi, Lopburi, and Singburi, making it long. The newly lengthened road was renamed Phahonyothin Road, in honor of General Phraya Phahol Pholphayuhasena (formerly Phot Phahonyothin), the second Prime Minister of Thailand and one of the heads of the 1932 revolution.
Route.
In Bangkok, Phahonyothin Road originates in Ratchathewi district and crosses Phaya Thai, Chatuchak, Bang Khen, and Don Mueang districts before continuing into Pathum Thani Province, and on through Ayutthaya, Saraburi, Lopburi, Nakhon Sawan, Chainat, again through Nakhon Sawan, Kamphaeng Phet, Tak, Lampang, Phayao and finally Chiang Rai, ending in Mae Sai district, where it connects to Tachileik in Myanmar.