The siege of Danzig took place between 1655 and 1660 when a Swedish force tried to capture this important Baltic Sea port city from the Polish–Lithuanian Commonwealth during the Second Northern War. After 5 years of fighting around Danzig (Gdańsk), the Swedish force which has made little ground surrendered.

Chronology

• 1655
  • Swedish naval forces blocked Danzig's harbor – trade was suspended.
  • Swedish land forces capture the fortress Danziger Haupt (Głowa Gdańska, Danzig Head) – very important water gate on Vistula River
• 1656, July – Dutch naval forces comes to Gdańsk Bay and unblock Danzig's harbor.
• 1656, September – Treaty of Elbing: siege lifted due to Dutch intervention
• 1659, 26 October – Poles defeated the Swedes in a skirmish near Danziger Haupt.
• 1659, 22 December – Swedish garrison of the fortress Danziger Haupt capitulated.
• 1660, May – Treaty of Oliva was signed. End of war.

Danzig all of that time was unconquered and remain loyal to Polish–Lithuanian Commonwealth.