The grave registry is described as:
The SUVCW National Graves Registration Project was established in 1996. Since then, hundreds of dedicated people from within and without our Order have graciously devoted thousands of hours of their time and energy visiting cemeteries, recording, verifying, researching and entering the final resting places of Civil War veterans. From the beginning, one thing was missing - the means for the SUVCW and general public to search and view the results of our labor on the Internet. As the number of registrations grew, it was also apparent that duplication of effort and waste of time was reaching an unacceptable level, without knowledge of what was completed and what needed further investigation.
You can input a surname and get a list of names with the state they served from, their unit and the cemetery location. You can click on the soldier's name and get more information - the cemetery, his birth and death dates, his service dates, and more.
I found 39 Seaver Civil War veterans, some of whom I don't have death dates for in my Seaver one-name study. My Isaac Seaver, buried in Leominster MA, is a Civil War veteran, but is not listed in this registry.
You can create a free account and submit more soldier names and their data to the registry.