Fort Stevens was built during the Civil War and used heavily during WWII to protect the Columbia River from Japanese submarines. In fact, 17 shells were fired onto the fort, but no serious damage was done. All that is left of the fort are the foundations of buildings and the cement gun batteries.
There is a small museum and gift shop run by camper-volunteers. These people volunteer as camp hosts and tour guides who also run the museum. In exchange, they get a free campsite for a couple of months commitment. I enjoyed chatting with them because they also are older retirees who live in motorhomes or fifth-wheel trailers for part or most of the year. Most of this group had homes in Oregon, but enjoy the activity and friendship with fellow volunteers so they volunteer each year for several months at various parks. One couple are in the campsite next to mine, so I had met them yesterday.
There is a walking tour of the batteries, but I chose the guided tour on the old truck. It turned out to be considerably bumpier than I had planned on.