Maentwrog is a village and community located in the Welsh county of Merionethshire, United Kingdom. It is situated within the Snowdonia National Park, specifically lying in the Vale of Ffestiniog just below the town of Blaenau Ffestiniog.
The village is positioned alongside the River Dwyryd. According to census data, the population grew from 585 in 2001 to 631 in 2011. The broader Community of Maentwrog also encompasses the village of Gellilydan.