| Official Name: | Phak Hai |
| Native Name: | ผักไห่ |
| Native Name Lang: | th |
| Settlement Type: | District |
| Subdivision Type: | Country |
| Subdivision Name: | Thailand |
| Subdivision Type1: | Province |
| Subdivision Name1: | Ayutthaya |
| Subdivision Type2: | Seat |
| Subdivision Name2: | Phak Hai |
| Subdivision Type3: | Tambon |
| Subdivision Name3: | 16 |
| Subdivision Type4: | Muban |
| Established Title: | District established |
| Population Total: | 44436 |
| Population As Of: | 2000 |
| Blank Name Sec1: | Postal code |
| Blank Info Sec1: | 13120 |
| Blank Name Sec2: | Geocode |
| Blank Info Sec2: | 1408 |
| Timezone: | ICT |
| Utc Offset: | +7 |
| Coordinates: | 14.4583°N 100.37°W |
Phak Hai (in Thai pronounced as /pʰàk hàj/) is a district (amphoe) in the northwestern part of Ayutthaya province, central Thailand.
Historically, the district was named Khwaeng Sena Yai, which became converted to an amphoe at the end of the 19th century. In 1917, the name of district was changed to be Phak Hai after the central tambon.
The name Phak Hai comes from the Nirat Suphan by Sunthorn Phu, which refers to a village named Ban Pak Hai. The spelling has changed however now, so it can also mean a kind of plant (Momordica charantia) that grows in swamps.[1] [2]
Neighboring districts are (from the north clockwise) Wiset Chai Chan and Pa Mok of Ang Thong province; Bang Ban, Sena, and Bang Sai of Ayutthaya Province; and Bang Pla Ma, and Mueang Suphanburi of Suphanburi province.
The district is divided into 16 sub-districts (tambon), which are further subdivided into 128 villages (muban).
| 1. | Phak Hai | ผักไห่ | ||
| 2. | Ammarit | อมฤต | ||
| 3. | Ban Khae | บ้านแค | ||
| 4. | Lat Nam Khem | ลาดน้ำเค็ม | ||
| 5. | Talan | ตาลาน | ||
| 6. | Tha Din Daeng | ท่าดินแดง | ||
| 7. | Don Lan | ดอนลาน | ||
| 8. | Na Khu | นาคู | ||
| 9. | Kudi | กุฎี | ||
| 10. | Lam Takhian | ลำตะเคียน | ||
| 11. | Khok Chang | โคกช้าง | ||
| 12. | Chakkarat | จักราช | ||
| 13. | Nong Nam Yai | หนองน้ำใหญ่ | ||
| 14. | Lat Chit | ลาดชิด | ||
| 15. | Na Khok | หน้าโคก | ||
| 16. | Ban Yai | บ้านใหญ่ |
Phak Hai is the setting of a Thai country song, (luk thung), titled (Thai: สาวผักไห่;) 'Phak Hai Girl'). It has been popular since around 1970s.[1]