I am 47 years old, and my mother asked if I knew how she could find out if she was devorced. My father left when I was one year old and we have no idea where he is today.
Where would I begin ?

Since you don't know where he's at or where he;s been, you might start by talking to any relatives that you know of.

If you could find where he's been living, you might be able to check the public records in that area.

Try searching on his name on the internet. You may be surprised.

If you can't locate him through family or the internet, your best bet would be a private investigator.

Forget trying to find out if she is divorced. Have her file for divorce. Many areas now have no fault divorces that make it easy.

One thing you could try is by doing a search at the courthouse where they lived at the time when he left. If nothing comes up there then file as has been said. Is there a reason she wants to know or doesn't know at all ?