The earliest known mention of a castle here dates from 1324, when the Lord of Bronckhorst commissioned the building. By 1392, the lending register of the lords of Bronckhorst recorded a property called Hacforden with an outer bailey and a moat. The medieval castle did not survive the chaos of the Eighty Years' War. In 1586, Spanish troops largely destroyed it. Borchard van Westerholt rebuilt it in 1598, marking the start of a Westerholt tenure that would last until 1981. In 1788, Borchard Frederic Willem van Westerholt remodeled the structure into the building you can still see today - a tighter facade with large windows and cross windows, shutters at the lower level, a symmetrical front no longer interrupted by the old gatehouse. The moat, by then more decorative than defensive, was filled in.

The provenance has a small, satisfying twist. In 1324, a Willem van Bronckhorst sold a share in a property he called Hacvorde to a man named Jacob van der Welle. Jacob promptly began styling himself Van Hackfort. The castle named its own owner. The Van Hackforts held it - with Van Bronckhorst remaining the feudal overlord, or leenheer, until 1702 - until the line ran out in the female heir Jacoba van Hackfort, whose marriage carried the property to the Van Raesfelt family in 1581. Their daughter Margarethe then passed it on to her cousin Borchard van Westerholt in 1602, the man who had already rebuilt it after the Spanish destruction. The Westerholts ran it as a barony for the next three hundred and seventy-nine years.

When Borchard Frederik Willem van Westerholt died in 1934, his five children inherited as joint heirs. Only Clara was married; she was evicted from the castle in 1935. The reasons are not fully documented, but the legal and social architecture of large rural estates in interwar Europe was unforgiving to family members who fell outside the inheritance plan. The four remaining siblings - Arend, Lady Emma, and two more sisters - each took a quarter share and continued to live there. They did not marry. They did not produce heirs. They did, however, plan. In 1964, the 'lady sister' died at The Hague and willed her quarter to Natuurmonumenten. That same year, Arend signed his own quarter over to the same trust. The transfer was happening in plain sight, in slow motion, while the family still occupied the rooms.

Arend van Westerholt died on 8 October 1970. His sister Lady Emma followed on 28 November 1971. The remaining sister, Sannie, then held the castle alone as the sole individual owner - the last Westerholt in a castle the family had held since 1602. She lived in it for a decade more. When she died on 14 April 1981, the final quarter share passed to Natuurmonumenten as the family had planned. There were no children. There was no dispute. A line that had renamed itself after a property in 1324 ended in 1981 by giving the property to a national trust that promised to keep it standing for everyone.

Hackfort does not stand alone. The castle is surrounded by forests and meadows and the working watermill of Hackfort, the kind of estate landscape that takes centuries to compose and minutes to admire. Natuurmonumenten manages the woods and the watercourses with the same care it gives to its national reserves. The castle itself is one of the eight castles around Vorden that earned the town its 1976 distinction as the pearl of Gelderland. Hackfort is open to visitors in season. The watermill turns. The Westerholt name no longer hangs on the doors. The castle is now owned, technically and in practice, by the country.