Brandalsund Manor, Manor house in Södertälje, Sweden.

Brandalsund is a manor house in Södertälje Municipality with classic Swedish architectural features, including a symmetrical facade and traditional proportions. The structure sits in a rural setting near the Stockholm County coastline.

The current manor was built between 1916 and 1918 by architect Thor Thorén and replaced earlier structures damaged during past conflicts. The site experienced multiple periods of destruction and reconstruction over several centuries.

The name likely refers to Brandaborg, a fortified medieval castle in the Södertälje area that guarded the inlet. Near the main building stands the moved runestone Södermanlands runinskrifter 350. The estate also included a brickworks northeast of the main buildings, closed in the 1860s; around 1900 lime-sandstone bricks were made for some of its own outbuildings, and Tegeltorpet south of the nature reserve remains from that period.

The manor is private and not open to the public. The 2,200-metre tree-lined avenue runs from county road AB 525, known as Utflyktsvägen, west to Trindborgen at Brandalsund. The buildings and the English park with its round red-brick water tower can be seen from the avenue.

The 19th-century main building was not demolished but dismantled in 1917 and shipped on barges across Lake Mälaren to Köping, where it was re-erected by 1918. The present manor, designed by Thor Thorén, was then built on the empty site in 1917–1918.