There are a variety of entrenchments at Fort Donelson. There are outer works which is a long trench with artillery positions. As the name suggests it is far away from the fort (and will be shown in a later post). There are two water batteries which were located right next to the river and were there to prevent Union gunboats from steaming up river. And then there was the fort itself. It was located on the high ground adjacent to the water batteries and was there basically to protect those batteries.
It also served as a campground for the troops especially int he early days of the fort when only 2-3 regiments were stationed here. As the threat from Grant developed more men came here and filled the outer lines. The park has two reproduction cabins so that you can see the kind of quarters the troops would enjoy. They claim there were about 400 of these huts. After the campaign Grant had these burned as they were a source of disease. New huts would be built to house the men that stayed in the area to secure the Union supply line.
Here are a variety of shots of the inner fort. It is in pretty good condition.