| Official Name: | Mueang Chai Nat |
| Native Name: | เมืองชัยนาท |
| Native Name Lang: | th |
| Settlement Type: | District |
| Subdivision Type: | Country |
| Subdivision Name: | Thailand |
| Subdivision Type1: | Province |
| Subdivision Name1: | Chai Nat |
| Subdivision Type2: | Seat |
| Subdivision Name2: | Nai Mueang |
| Population Total: | 72031 |
| Population As Of: | 2008 |
| Blank Name Sec1: | Postal code |
| Blank Info Sec1: | 17000 |
| Blank Name Sec2: | Geocode |
| Blank Info Sec2: | 1801 |
| Timezone: | ICT |
| Utc Offset: | +7 |
| Coordinates: | 15.1856°N 100.1239°W |
Mueang Chai Nat (in Thai pronounced as /mɯ̄a̯ŋ t͡ɕʰāj nâːt/) is the capital district (amphoe mueang) of Chai Nat province, central Thailand.
Neighbouring districts are (from the east clockwise) Sapphaya, Sankhaburi, Hankha, Wat Sing, and Manorom of Chai Nat province; and Takhli of Nakhon Sawan province.
On 29 April 1917 the district's name was changed from Mueang to Ban Kluai (บ้านกล้วย).[1] On 14 November 1938 it was renamed Mueang Chai Nat.[2]
The district is divided into nine sub-districts (tambons), which are further subdivided into 81 villages (mubans). Chai Nat is a town (thesaban mueang) which covers tambon Nai Mueang and parts of Ban Kluai, Tha Chai, and Khao Tha Phra. There are a further eight tambon administrative organizations (TAO).
| No. | Name | Thai | Villages | Pop.[3] | |
|---|---|---|---|---|---|
| 1. | Nai Mueang | ในเมือง | - | 5,861 | |
| 2. | Ban Kluai | บ้านกล้วย | 7 | 13,379 | |
| 3. | Tha Chai | ท่าชัย | 11 | 8,801 | |
| 4. | Chai Nat | ชัยนาท | 9 | 8,259 | |
| 5. | Khao Tha Phra | เขาท่าพระ | 7 | 7,552 | |
| 6. | Hat Tha Sao | หาดท่าเสา | 8 | 5,031 | |
| 7. | Thammamun | ธรรมามูล | 10 | 7,547 | |
| 8. | Suea Hok | เสือโฮก | 14 | 7,682 | |
| 9. | Nang Lue | นางลือ | 15 | 7,919 |