Aalborghus Castle (Danish: Aalborghus Slot) is a castle in Aalborg, Denmark. It is a half-timbered (bindingsværk) castle built by King Christian III from 1539 to around 1555 initially as a fortification. Soon it became the seat of the king's provincial governors in Northern Jutland, and after the introduction of absolutism, became used by the State County of Northern Jutland for taxes.