9 May – Denmark wins a tactical victory in the Battle of Heligoland but it has no impact on the outcome of the war.
12 May – A general armistice came into effect, Denmark has lost the war.
June
29 June – In the Battle of Als, the last major engagement of the war, the Prussians secure Als after a night attack masterminded by the Chief of Staff Leonhard Graf von Blumenthal.
July
3 July – The Battle of Lundby in north-eastern Himmerland results in great Danish losses. It becomes the last battle of the Second Schleswig War.
