Thong Pha Phum (, ) is a district (amphoe) in the northern part of Kanchanaburi province, central Thailand and is located west of Bangkok.
At first Thong Pha Phum was the minor district (king amphoe) Sangkhla Buri, a subordinate of Wang Ka District. In 1939 the name Sangkhla Buri was assigned to Wang Ka, while the minor district was renamed Thong Pha Phum. On 20 May 1941 it was upgraded to a full district, while at the same time Sangkhla Buri was reduced to a minor district. It then consisted of the six tambons Tha Khanun, Hin Dat, Dika, Chalae, Pilok, and Linthin.
Neighboring are (from west clockwise) Tanintharyi Division of Myanmar, Sangkhla Buri of Kanchanaburi province, Umphang of Tak province, Ban Rai of Uthai Thani province, Si Sawat and Sai Yok of Kanchanaburi province.
The district's important water resource is the Khwae Noi River, which is dammed by the district's Vajiralongkorn Dam.
Thong Pha Phum, Lam Khlong Ngu, Khuean Srinagarindra, and Khao Laem National Parks are found in the district.
The economy includes the 460 million baht cleanup of the lead tailings in Klity Creek, caused by a now-closed lead processing factory; the cleanup is "the first state-supervised environmental cleanup in Thailand". The Bo Ngam lead mine severely contaminated the soil, where the lead content was as high at 15%. Despite this, 48 species of plants were found growing in the area, suggesting possible bioremediation.
Thong Pha Phum district has a tropical savanna climate (Köppen climate classification Aw). Winters are dry and very warm. Temperatures rise until April, which is very hot with the average daily maximum at . The monsoon season runs from May through October, with heavy rain and somewhat cooler temparatures during the day, although nights remain warm.
The district is divided into seven subdistricts (tambons), which are further subdivided into 45 administrative villages (mubans).
As of December 2024 there are: four municipal (thesaban) areas in the district; these are subdistrict municipalities (thesaban tambons) of which Linthin and Sahakon Nikhon cover the whole subdistrict, Thong Pha Phum covers only village no.1 of Tha Kanun subdistrict and Tha Kanun covers the remaining of the same named subdistrict.
The non-municipal areas are administered by four subdistrict administrative organizations - SAO (ongkan borihan suan tambon - o bo toh).
Thong Pha Phum district is served by one hospital
In the district there are thirteen health-promoting hospitals in total.
There are fifty-nine Theravada Buddhist temples in the district.
The Christians have twelve churches and muslims have two mosques.