3 Major Credit Bureaus
To get the whole picture, contact all three credit bureaus.

There are three main credit bureaus reporting on consumer behavior. Each collects information in its own unique way so it is important to monitor all three, not just one.
TransUnion, Equifax, and Experian all gather and analyze data independently. They do not share with one another, and they do not share their exact methodologies. The only thing that can be said for sure is that credit reports and scores from the three companies can vary widely, even shockingly.
Anyway, you can obtain one free credit report per year from each bureau by calling them, then waiting for the report to arrive in the mail. Here are the numbers:
Equifax: 866 640-2273
Experian: 800 493-1058
Trans Union: 800 916-8800
It is also possible to contact the credit reporting agencies by mail, but who wants to go through all that?
You can also check all three right now for free and have them all in minutes. If you like the service, you can monitor them all continuously and never worry about it again!