Hamilton Mausoleum is a mausoleum located in Hamilton, South Lanarkshire, Scotland. It was the resting place of the family of the Dukes of Hamilton. Built in the grounds of the now-demolished Hamilton Palace, its high stone used to hold the record for the longest echo in the world, taking 15 seconds for the sound of a slammed door to decay. In 2012 the record was broken at the Inchindown oil storage tanks in the Scottish Highlands. It is now closed to the public.
In line with his grandiose enlargement of Hamilton Palace, Alexander, 10th Duke of Hamilton, replaced his family burial vault which stood close to the east quarter of the palace in the aisle of the old and dilapidated collegiate church. Now the solitary remaining testament to the colossal scale and grandeur of the buildings which once stood in Hamilton Low Parks, Hamilton Palace Mausoleum is a Roman-style domed structure of panelled masonry. Standing to an overall height of about 123 feet (37 m), it occupies a site some 650 feet (200 m) north of the site of Hamilton Palace. Construction was begun in 1842 by architect David Hamilton and completed by architects David Bryce and sculptor Alexander Handyside Ritchie in 1858, five years after the death of the 10th Duke. The Duke was interred in an Egyptian sarcophagus of the Ptolemaic period, on a black marble slab in the main chapel, while 17 of his ancestors were interred in the crypt below. The coffins of the 10th Duke and his ancestors were later removed after subsidence and flooding from the River Clyde affected the mausoleum, and were re-buried in Hamilton's Bent Cemetery.
During the 1960s and 1970s the structure was observed to be subsiding, and a 20-foot (6-metre) plumb-line hanging on the front of the mausoleum indicated a lean from true verticality. The monolithic, plinth-based construction prevented structural cracking however, and, after many anxious years, the building settled back to near vertical (180 degrees).