In Thailand, which provinces apply Islamic family law?

Only four provinces: Pattani, Narathiwat, Yala and Satun, under the Act on the Application of Islamic Law B.E. 2489 (1946). There, in civil cases on family and inheritance between Muslims, Islamic law applies in place of the Civil and Commercial Code (s.3). A Dato' Yutitham sits with the judge and his ruling on Islamic law is final (s.4). The Act does not create separate Syariah courts. Songkhla is not included even though some of its districts have large Muslim populations; Muslim family disputes there are decided under the monogamous Civil Code. Act 1946 also has no polygyny permission procedure or specific penalties. See Thailand.