The name Logan has complicated origins.
The Logans of the Northern counties are generally of Scottish stock. Many of them came to Ireland during the Plantation of Ulster in the early 17th century.
In the counties of Galway and Westmeath there are Logans whose names are derived from the Irish O'Loughan, which is also anglicized as Lohan, like American teen movie queen, Lindsay Lohan (1986). The name has also been subject to an absurd anglicization because of the similarity of the name to the Irish word, lacha, meaning duck.
Some famous Logans include County Antrim man James Logan (1674-1751), an associate of William Penn who held several high positions in Pennsylvania government, and Lt. General Edward Lawrence Logan (1875-1939) who was a fixture in Massachusetts state politics and for whom Logan International Airport in Boston is named.