Recently, while researching for 19th Century persons, I discovered two sites that had Civil War records. Both of them had images of a series of books titled The War of the Rebellion: A Compilation of the Official Records of the Union and Confederate Armies. These books include typewritten copies of official correspondence, orders, reports and returns from both sides of the war. This series was published in the late 1800s and early 1900s by the Washington Government Printing Office.
Below are the advantages and disadvantates of each site:
* Google Books has a search engine that allows you to look up specific names, places and events. Once you are on the page you are looking for, it even highlights the words that you are searching for. The entire series appears to be on this site, the only problem is that it is not organized. You have to search through the entire series in order to find a specific volume in the series. Books may be downloaded on to PDF for easy viewing and printing. Series Link
* Cornell University Library "Making of America" has the entire series organized on one webpage. As with the Google site, the series is searchable; however, it does not highlight the terms you are looking for once you get on to the page. It is not possible to download the books on to PDF, and you may only print page by page. In order to print a page, you must right click and click "print page". Also, if you wish to look at another page, you must type in that page number in the box at the top of the web page. Series Link
You may also find on these sites the series Official Records of the Union and Confederate Navies in the War of the Rebellion. The same advantages and disadvantages exist for this series on those sites. To access this series, click on the links below:
* Google Books - Union and Confederate Navies
* Cornell University - Union and Confederate Navies