How to make the continue button on the log off page link to website root?

Can someone please tell me what file and where in the file I can change the link of my log off pages continue button. I would like to make it so when the customer clicks continue it takes them to my root homepage.

Thank you for any help.

Bunyip has answered this for me. Thank Bunyip! The file is tpl_logoff_default.php under the template directory.