Today, on the east side of Plum Island, a network of trenches remains from the area's tenure as an artillery post.

The name never caught on and was later applied to an artillery post at the Presidio.

The fortification complex consists of individual artillery posts grouped together into strategic points.

Fort Columbia is an old coastal artillery post along the north side of the Columbia river outlet.

Skills: Driving tanks and vehicles, capturing heavy machinegun and artillery posts.

These were what he was trying to construct in the stretches between the artillery posts, although he still did not have the army to man them.

These would provide data for the central artillery post to calculate and then transmit to the guns for the gun crew to follow.

Early on the morning of June 6, 1944, he had looked out from his forward artillery post and had seen the Allied invasion fleet.

Because of this fatal design flaw, the fort was removed from the list of active coastal artillery posts in 1909.

During the American Civil War, the military established a defensive coastal artillery post and garrison at this location.