Landhaus Baur, Country house in Nienstedten, Germany.

Landhaus Baur is a neoclassical country house in Nienstedten with a striking two-story circular main hall whose dome rises 10 meters high and features Corinthian pilasters and sculptural figures in wall niches. The roughly 600-square-meter building contains about 20 rooms and currently serves as headquarters for the Hermann Reemtsma Foundation.

Johann Heinrich Baur, an Altona merchant and banker, acquired the land between today's Elbschloßstraße, Christian-F.-Hansen-Straße and Elbchaussee in 1803 and 1806. He had Christian Frederik Hansen, a Danish classicism architect, build a garden house modelled on Rome's Pantheon and Palladio's villas. After Baur's early death in 1807, his brother Georg Friedrich Baur bought the property. The Elbschloss-Brauerei owned it from 1882 until 1997, and the Hermann Reemtsma Stiftung has held it since 2000.

The name "Elbschlösschen" comes from the building's villa-like form on the Elbchaussee. From 1882 the estate belonged to the Elbschloss-Brauerei, which used the house as its administration until the brewery closed in 1997. Since 2000 it has housed the Hermann Reemtsma Stiftung.

The house sits in the villa district of Nienstedten along the Elbe River, reachable by public transport. Visitors should check ahead of time whether tours are possible and under what conditions, as the building primarily functions as a working office today.

A 1943 bomb struck the building, and the 2002–2003 restoration by Alk Arwed Friedrichsen also removed a 1960s duplex and part of the neighbouring malthouse that had come within eight metres of the house from the south.