The Battle of Grengam (Russian: Гренгамское морское сражение, Swedish: Slaget vid Ledsund, or Slaget vid Föglöfjärden. ) of 1720 was the last major naval battle in the Great Northern War that took place in the Åland Islands, in the Ledsund strait between the island communities of Föglö and Lemland. The battle marked the end of Russian and Swedish offensive naval operations in Baltic waters.