Mērsrags (German: Markgrafen) is a small harbor town in Talsi Municipality in the Courland region of Latvia, located on the west coast of the Gulf of Riga beside Lake Engure and surrounded by extensive woodlands. The total area of the former Mērsrags municipality was 109 km (10896.2 ha), 63.7% of this area was woodland and Lake Engure covered 20.4%, the coastline was about 12 km long. The town center is some 42 km from Talsi, the main city of the area and some 95 km from the capital, Riga.
Mērsrags had a population of 1986 in June 2008.