To check it out, go to archives.gov, then to “Research Our Records.” From there, select “Research in the National Archives Catalog,” and then “Search the Catalog.” As with any website, it can’t hurt to read the instructions. I found just a basic search turned up many important sources, especially if the surname is an unusual one.
The catalog links you to any federal record that has been put into this system: Revolutionary War pensions, military service records, some War of 1812 pensions. The best part of this, some other names within the pensions are now searchable, a feature I do not recall on other sites. Presidential Library collections are included. The1841 Bankruptcy records are also linked, as are some immigration and census records. All in all, it is a good place to check, search and see what leads you get. While some records, such as military records, can be read right there, for others contact a NARA branch.