The Winter War between Finland and the Soviet Union finished with the Moscow Peace Treaty signed on March 12, 1940. One of the consequences of the treaty was the lease of Hanko Peninsula to USSR for 30 years. This peninsula was to be used as a naval base by the Soviets, so from March 22 on (when Finnish delivered them the base) USSR started moving troops to the peninsula.
In that context, Operation Barbarossa started on June 22, 1941. Finland alligned itself with Germany and agreed to give access to Finnish land to the German troops as well as allocating troops to conquer back the land lost during Winter War.
Before the battle
On June 22, 1941 when the Operation Barbarossa started, the Soviet Union had 25.300 troops defending the Peninsula. 4.500 Soviet civilians were also in Hanko. The Soviet troops located in the peninsula were parte of:
- 8th rifle brigade
- 343rd artillery regiment
- 297th tank batallion
- 204th anti-aircraft artillery division
- Other additional units
On top of those units, the defenders some artillery batteries. Among them, there were 2 rail artillery batteries with 3 TM-3-12 and 4 TM-1-180 very-heavy rail guns.
The Finnish Army created the Hanko group in order to conquer Hanko Peninsula. Firstly, it was formed by the 13th brigade and the 4th coastal brigade but the first one was finally replaced by the 17th infantry division. Some other additional units complete the 18.066 troops that Finland was deploying on June 25, 1941. 10 days later, on July 5th, Finnish troops increased to 22.285 soldiers.
The 163th German infantry division was also supposed to take part in the attack, but it was finally sent to Karelia, as the Red Army defense there was stronger than expected by the attackers.
During the battle
Even though the conquer of Hanko was among the main Finnish goals before the war, finally Finland moved their troops to Harparskog fortified line, built during the interwar period. Then, the battle was mainly static, but both participants launched some small-scale amphibious landings. The first of them was the Soviet landing in Bengtskär, where Soviets did not manage to take control of the island.
In the sea, attackers tried to blockade Hanko but they were unable to do so. Even then, for the defenders was very hard and costly to keep supplying Hanko as Finland used to attack supply ships also with mines.
Finally, the Soviet Union ordered its troops to evacuate Hanko in autumn 1941. Then, from October 16 to December 2 Soviet vessels managed to evacuate 23.000 troops, but suffering heavy losses due to Finnish mines and artillery: 3 destroyers and 2 big transport vessels were lost during the evacuation.
Battle of Hanko gave Axis troops control of the south of Finland. Finnish troops suffered 297 killed, 604 wounded and 78 missing, while Soviet troops suffered 797 killed and 1.476 wounded without bearing in mind the casualties suffered during the evacuation.
“Battle of Hanko (1941)”. Wikipedia. 01-02 April 2020. <https://en.wikipedia.org/wiki/Battle_of_Hanko_(1941)>
“Оборона Ханко”. Wikipedia (russian). 01-02 April 2020. <https://ru.wikipedia.org/wiki/%D0%9E%D0%B1%D0%BE%D1%80%D0%BE%D0%BD%D0%B0_%D0%A5%D0%B0%D0%BD%D0%BA%D0%BE>
“Battle of Hanko 1941”. Naval Encyclopedia. 01-02 April 2020. <https://www.naval-encyclopedia.com/ww2/battles/Hanko-peninsula-1941>