I recently came across a new source for information on those who served in the civil war. It’s called the Civil War Soldiers & Sailors System. What I didn’t expect was to find that it wasn’t maintained by the National Archives, but rather the National Park System. There was quite a lot of information that was available through different types of searches. I’ve mostly used the ‘Soldiers’ search function, but plan on spending some time looking through the cemeteries soon also.
As for the information it holds, the soldiers records didn’t really contain any biographical or genealogical data. However, it does place these individuals in a location and time period and notes the type of regiment they served in and, of course, whether they fought for the union or the confederacy. I was surprised to find ancestors from the south that were fighting union regiments. Definitely not what I expected.
There is information on over 6.3 million soldiers and sailors who fought in the civil war. The database was compiled in 2004 by volunteers and then edited for accuracy by NPS staff. It contains histories of Union and Confederate regiments, links to descriptions of 384 significant battles of the war, and other historical information.They also plan on adding more info about soldiers, sailors, regiments, and battles, as well as prisoner-of-war records and cemetery records.
If you have ancestors that lived in the U.S. during the Civil War period, it’s definitely worth a little time to see what might be in this collection.
Family History Alive 
The Civil War Soldiers System is a site near and dear to my heart! (I was the coordinator for the entry of the Ohio soldiers.) I’m glad you found it! Definitely explore the regimental histories and the battle summaries. They are excellent resources for putting your Civil War ancestors into context.