Sânmartin or Csíkszentmárton (Sânmartin, Csíkszentmárton) is a commune in Harghita County, Romania comprising 3 villages:
- Valea Uzului/Uzvölgye
- Cozmeni (Csíkkozmás) along with the village of Lăzăreşti (Lázárfalva) have formed an independent commune since 2002.
The commune has an absolute Székely Hungarian
majority. According to the 2002
census it has a population of 4,334 of which 97% or 4,204 are Hungarian
. Since 2002 the smaller commune itself has a population of 2,351.