This state park abuts the Jacksonville-Baldwin Rail Trail and a sidewalk connects the bike path rest area with the state historic park, which is how I discovered it today. I biked over to explore and spent 40 minutes learning about events I had never even dreamed of.
For example, during the Civil War, Florida was important to the Confederacy, having supplied over 16,000 troops to the army, and also contributing fish, fruit, pork, beef, and salt to the Confederate troops. The Union army recognized Jacksonville's importance to the Confederacy and wished to interrupt the supply lines, so they invaded the area four times during the war, more than any other city in the Confederacy.
In 1864, Camp Milton was considered the largest encampment of Confederate forces in Florida with over 8,000 troops. The site of several encounters between Confederate and Union armies, the camp finally fell to occupation by the Union army in the summer of 1864. It is named after Florida's Governor during the Civil War, John Milton.
The drawing below shows the extensive defensive fortifications constructed by slaves and soldiers in 1864. (Click to enlarge.)
Located west of McGirts Creek, Camp Milton became the eastern Florida military headquarters for the Confederate States of America, housing 6,000 infantry, 1,500 calvary, and 430 field pieces.
The goal of these fortification was to block Union advances along Old Plank Road and the Florida, Atlantic and Gulf Central Railroad toward Baldwin, Florida, which served as an important Confederate supply center and railhead. Below is a replica of the traditional "Campaign Bridge" that troops would have hastily constructed to move weapons an supplies over waterways...
The area has undergone extensive archeological excavation by professionals to locate artifacts and enable them to reconstruct historically accurate earthworks and wooden fortifications. Below is a sample of wooden fortifications (click to enlarge)...
...and they have determined that 15,840 linear feet of earthworks had been dug, and though only about 725 feet still remain, that number represents the largest intact remnants around.
Sometimes referred to as earth-works, field-works, breast-works, or just simply works, this fortification built by the Confederate Army helped protect their position against advancing union soldiers. On the earthworks, vertical logs were fastened upright with loopholes for riflemen to stand every two feet apart and platforms were built to place their heavy artillery, such as cannons. After Federal forces overwhelmed the Confederate army and took over Camp Milton, Union General George H. Gordon inspected the “breast-works” and described them as “most solidly constructed and beautifully finished."