Si Ayutthaya Road is a road in inner Bangkok. It starts from Ratchaprarop Road at Makkasan Intersection in the Ratchathewi district and runs eastward, crossing Phaya Thai Road, Rama VI Road, Kamphaeng Phet 5 Road, and the northern railway line. It then enters Dusit district, passing many important sites such as Dusit Palace, Wat Benchamabophit, the Royal Plaza, Paruskavan Palace, before ending at the intersection with Samsen Road near the Chao Phraya River at Si Sao Thewet Intersection.