Karelian Fortified Region

22nd Karelian Fortified Region (KaUR; Карельский укрепленный район; Карельский укрепрайон; КаУР) is a 60 km wide area of Soviet defensive fortifications to the north of Leningrad (now Saint Petersburg) that was built in 1928-1932, 1938-1939, 1941-1944 and 1950-1965 in the Soviet part of Karelian Isthmus among other fortified areas (so called Stalin Line) constructed around that time in order to protect western borders of the Soviet Union. KaUR spans along the old Finno-Russian border from Valkeasaari near the northern shore of the Gulf of Finland through Lempaala to Nizhniye Nikulyasy Bay on the western shore of Lake Ladoga.

Its commander in 1941 was General Major Mikhail Andrianovich Popov.

Among Soviet definitions of Fortified Regions were: "Fortified Region" a fortified area, equipped in engineering terms for defence, line of defense in the form of long-term centers of resistance strongholds that are in interaction and forming general group (tens of kilometers of engineering structures, different obstacles, managed and unmanaged minefields), and garrison troops (see Fortified area troops) designed to perform defensive tasks. Fortified area, as a system of permanent fortifications, permanent resistance in these special garrisons and combined arms.

Restricting your opponent for all his front e, they create the possibility of concentration of large forces and means for applying the enemy crushing blows in other areas. Troops battling in fortified areas require special tenacity, endurance and stamina.