Store Frederikslund is a manor house and estate located eight kilometres northeast of Slagelse, Slagelse Municipality, Denmark. It is one of several estates that was established when Antvorskov Cavalry District was sold in public auction. It was established by General Hans Henrik von Eickstedt in 1783 and later owned by the Castenschiold/Grevenkop-Castenschiolds family from 1786 to 1995. The Neoclassical main building from the 1780s was probably designed by Andreas Kirkerup. It was listed on the Danish registry of protected buildings and places in 1918.

Slagelse Municipality is a kommune in Region Zealand on the west coast of the island of Zealand in Denmark. The municipality covers an area of 571 km2. The municipality borders Kalundborg Municipality to the north, Sorø Municipality to the north-east, Næstved Municipality to the south-east and connects to Nyborg Municipality via the Great Belt Bridge.