Photoshop exports images several times larger than the original size.

I am attempting to create a book using photoshop.  I'm trying to export images that are 8.5 x 8.5 inches.  When I create new files for each page, I set the canvas size as 8.5' x 8.5' with a resolution of 300 pixels/inch.  However, when I export the file, instead of exporting it as 8.5 x 8.5, the exported file will be inexplicably 35.417' x 35.417'   I do not understand why photoshop is doing this, nor how to fix it.  Can somebody please help me?