Hegra Fortress is a small mountain fortress in the village of Hegra in the municipality of Stjørdal in Nord-Trøndelag county, Norway. Originally known as Ingstadkleiven Fort, it was built between 1908–1910 as a border fort as a defence against the perceived threat of a Swedish invasion.
In 1940, from 15 April to 5 May, Hegra was attacked by the German invaders. During the first week the attacks consisted of two infantry assaults; however in the last two weeks attacks mostly featured heavy artillery fire and Luftwaffe bombing, as well as aggressive patrolling.
During the siege large portions of the fort were covered in snow, and as all plans of the fort were stored in German-occupied Trondheim several sections of the fortifications were not discovered by the defenders before the 5 May surrender.