Sichon district is in the northern part of the province. Neighboring districts are (from the south clockwise) Tha Sala and Nopphitam of Nakhon Si Thammarat Province, Kanchanadit and Don Sak of Surat Thani Province, and Khanom of Nakhon Si Thammarat. To the east is the Gulf of Thailand. Within the district is Namtok Si Khit National Park is in the district. In Sao Phao sub-district there is evidence of an ancient Shivite civilisation, 7th-9th Century at Khao Kha Archeological Site.