| Official Name: | Phra Nakhon Si Ayutthaya |
| Native Name: | พระนครศรีอยุธยา |
| Native Name Lang: | th |
| Settlement Type: | District |
| Subdivision Type: | Country |
| Subdivision Name: | Thailand |
| Subdivision Type1: | Province |
| Subdivision Name1: | Phra Nakhon Si Ayutthaya |
| Subdivision Type2: | Seat |
| Subdivision Name2: | Ho Rattanachai |
| Subdivision Type3: | Tambon |
| Subdivision Type4: | Muban |
| Established Title: | District established |
| Population Total: | 136467 |
| Population As Of: | 5 December 1998 |
| Blank Name Sec1: | Postal code |
| Blank Info Sec1: | 13000 |
| Blank Name Sec2: | Geocode |
| Blank Info Sec2: | 1401 |
| Timezone: | ICT |
| Utc Offset: | +7 |
| Coordinates: | 14.3522°N 100.5767°W |
Phra Nakhon Si Ayutthaya (Thai: พระนครศรีอยุธยา, in Thai pronounced as /pʰráʔ ná(ʔ).kʰɔ̄ːn sǐː ʔā.jút.tʰā.jāː/) is the capital district (amphoe Mueang) of Phra Nakhon Si Ayutthaya province, central Thailand. Its former name as the capital city of Ayutthaya Kingdom was "Krungthep Thawarawadi Si Ayutthaya" (Thai: กรุงเทพทวารวดีศรีอยุธยา).
According to George Coedes, tradition states Ramathibodi I founded Dvaravati Sri Ayudhya in 1350.[1]
Created in 1897, the district was originally called Rop Krung (รอบกรุง). The district name was changed to Krung Kao (กรุงเก่า) in 1917.[2] In 1957 the name was changed to Phra Nakhon Si Ayutthaya.[3] to commemorate the old capital city of the Ayutthaya Kingdom. This makes it unique among Thailand's capital districts, the rest of which are named amphoe mueang followed by the name of province.
Neighboring districts are (from the north clockwise) Bang Pahan, Nakhon Luang, Uthai, Bang Pa-in, Bang Sai and Bang Ban.
The district is divided into 21 sub-districts (tambon). In addition to the city (thesaban nakhon) of Ayutthaya there are other municipal areas. Ayothaya is a town (thesaban mueang) which covers part of the tambons Phai Ling, Hantra, and Khlong Suan Phlu.
| No. | Name | Thai | Pop. | |
|---|---|---|---|---|
| 1. | Pratu Chai | ประตูชัย | 16,155 | |
| 2. | Kamang | กะมัง | 1,458 | |
| 3. | Ho Rattanachai | หอรัตนไชย | 11,671 | |
| 4. | Hua Ro | หัวรอ | 12,427 | |
| 5. | Tha Wasukri | ท่าวาสุกรี | 8,756 | |
| 6. | Phai Ling | ไผ่ลิง | 15,232 | |
| 7. | Pak Kran | ปากกราน | 5,526 | |
| 8. | Phukhao Thong | ภูเขาทอง | 2,748 | |
| 9. | Samphao Lom | สำเภาล่ม | 6,368 | |
| 10. | Suan Phrik | สวนพริก | 3,941 | |
| 11. | Khlong Takhian | คลองตะเคียน | 4,798 | |
| 12. | Wat Tum | วัดตูม | 4,219 | |
| 13. | Hantra | หันตรา | 7,261 | |
| 14. | Lumphli | ลุมพลี | 5,083 | |
| 15. | Ban Mai | บ้านใหม่ | 4,415 | |
| 16. | Ban Ko | บ้านเกาะ | 4,892 | |
| 17. | Khlong Suan Phlu | คลองสวนพลู | 6,605 | |
| 18. | Khlong Sa Bua | คลองสระบัว | 4,380 | |
| 19. | Ko Rian | เกาะเรียน | 2,619 | |
| 20. | Ban Pom | บ้านป้อม | 6,504 | |
| 21. | Ban Run | บ้านรุน | 1,409 |
. George Coedès. Walter F. Vella. trans.Susan Brown Cowing. The Indianized States of Southeast Asia. 1968. University of Hawaii Press. 978-0-8248-0368-1.