Laa Castle stands in the northeast corner of Burgplatz. An imposing building made of stone walls with a butter churn tower and a low square battle tower was mainly used to supply and secure the weir. The castle was built in the 13th century. In 1564 almost the entire town and parts of the fortifications and the castle were burnt down by a conflagration. Around 1786 the castle went into private ownership.
In 2007, Laa Castle was bought by the municipality of Laa. The castle has been renovated in recent years and since 2018 the butter churn tower and the inner courtyard of the castle have been open to the public every day from 10 a.m. to 6 p.m.
In November 2019, the castle hall and the toilet facilities were also presented to the public.
The Laaer beer museum can be visited in the south wing.