Social and religious historians have conducted much research on Scottish colonial migrations to Ulster; however, there remains historical debate as to whether the Irish Sea in the seventeenth century was an intervening obstacle or a transportation artery. Vann presents a geographical perspective on the topic, showing that most population flows involving southwest Scotland during the first half of the seventeenth century were directed across the Irish Sea via centuries-old sea routes that had allowed for the formation of evolving cultural areas. As political or religious motivational factors...