This article tells of a secret hidden in the 1840 census. Click below to go to the link.
Here is a quick summary. On the back of the 1840 census, they listed veterans. This would include Revolutionary War veterans. In addition, if it was a widow receiving the pension, she would be listed.
An additional resource given is a published book with lists according to state. You can find this at archive.org. Here is a link to the book. https://archive.org/details/censusofpensione00usce