During the Civil War, although all of the serious fighting occurred far beyond the boundaries of Maine, there was action off the coast. A contemporary newspaper(Quoted in Louis Hatch's 1919 "Maine - A History") pointed out that: "Maine has an immense property interest in navigation. The keels of her thousands ships vex the waters of all the seas around the globe. It is all-important that they should be protected and our numerous but unprotected harbors into which they bow their welcome returns should be fortified…" Recognizing this need, the government ordered the defenses of the coast strengthened, including garrisoning Fort O'Brien. The effect of the war on ordinary people in Washington County was quoted by Lura Beam in A Maine Hamlet: "The Civil War made everybody poor for a long time. Families were scarred for forty years afterwards by the illnesses the fathers brought back, by the mortgages, the high cost of bare subsistence, the memories."

Climate - Daytime temperatures average above 18 degrees Fahrenheit during the winters and above 68 degrees Fahrenheit during the summers. The region receives an average of more than 44 inches of precipitation each year.

Visitor Information: Viewing historic sites and picnicking are enjoyed at this Down East fort between Memorial Day and Labor Day each year.