Slot Assumburg is a castle in the east of Heemskerk in the province of North Holland in the Netherlands.

However, the many finds of Kloostermoppen (large medieval bricks), and pottery from earlier times made it quite certain that the current castle had a predecessor.

[1] It probably dates originally from the 13th century, but was renovated in 1546 and is named after the hamlet of Assum between Heemskerk and Uitgeest.

It is assumed that demolition material from Oud Haerlem Castle was used in the construction, but that is not the case.

Afterwards Barthoud (I) dedicated the entire Assumburg to Mr. Jan I van Polanen (owner of the Oud Haerlem castle ), who lent him it on June 5, 1335.

Barthoud was married to Catharina, daughter of Dirk van den Wale, steward of Count Willem III.

His eldest son Dirk (I) obtained the Assumburg, but died childless shortly afterwards, so that his younger brother Gerrit (II) could settle in this castle in 1348.

So brother Dirk (II) van Assendelft moved into the Assumburg in 1413 and was even lend (April 20, 1421).

Renesses continued to live on the Assumburg for several decades, but in 1669 merchant Johannes Wuijtiers bought the castle.

When his wife Josina Johanna Willink died in Amsterdam in 1867, that was also the end of the Assumburg as a considerable country retreat.

After having been rented to the Hague city councilor Hugh Hope Loudon for a year(1816-1891), the building was given various functions: in 1881 as a hospital during a cholera epidemic and later as a school.

On July 15, 1933, the first young people found shelter here, unemployed youth hostel friends did a lot of work as part of the restoration.