Sometime before 3000 BC the local people raised Lligwy's 25-tonne capstone into place, forming a stone chamber that they covered with an earthen mound. When the barrow was excavated in 1908, the bones of about 30 people were found buried within. To find it, look for the country lane marked "Ancient Monument" near the roundabout on the approach to Moelfre. Park at the marked car park and walk back along the road; the chamber is on the right.
Signposted nearby are the remains of the Romano-British farmstead of Din Lligwy, dating back to the 1st century AD, and the ruin of the 12th-century Capel Lligwy chapel.
