Koartwâld, or Feanstermoune is a smock mill in Surhuisterveen, Friesland, Netherlands, which was built in 1864 and has been restored to working order.

In 1850, a post mill was built on the opposite side of the road to Koartwâld.

A storm on 24 September 1946 decapitated the mill,[2] damaging the stage, which was then removed.

[3] In 1990, a society was formed with the intention of restoring the mill to working order.

The sails are carried on a cast-iron windshaft, which was cast by the IJzergieterij De Prins van Oranje, The Hague, South Holland in 1889.

[3] Auxiliary power is a single-cylinder two-stroke 50 horsepower (37 kW) Brons diesel engine dating from 1933.