Barangay Cangmatnog is a barangay located in the municipality of Siquijor, within the province of Siquijor, Philippines. As of the 2020 Census, it has a population of 225 residents, accounting for approximately 0.78% of the municipality’s total population. Geographically, Cangmatnog is situated at approximately 9.1613° North latitude and 123.5698° East longitude, with an elevation of about 333.2 meters (1,093.2 feet) above sea level.

While specific historical records about Barangay Cangmatnog are limited, its demographic trends over the past decades provide some insights. The population has seen fluctuations, with a notable decrease from 188 residents in 1990 to 137 in 2000, followed by growth reaching 225 by 2020. These changes suggest periods of migration or other socio-economic factors influencing the barangay’s population dynamics.

Cangmatnog shares boundaries with several adjacent barangays, including Cang-atuyom, Cantabon, Luzong, Cang-asa, Ponong, and Tebjong, all within the municipality of Siquijor.