Southwest Friesland is a municipality in the northern Netherlands, located in the province of Friesland. It had a population of 89,999 in January …Southwest Friesland is a municipality in the northern Netherlands, located in the province of Friesland. It had a population of 89,999 in January 2021. Sneek is the municipal seat. With a total area of 841.56 km², Súdwest-Fryslân is the largest municipality by area in the Netherlands.