A turtle?

So this morning I was opening my bathroom window because it was so hot and I spotted this large animal creeping across my back lawn. I could tell that it wasn't a cat (because it was MUCH bigger)... so I ran downstairs to get my glasses so that I could actually see. :) When I got back, I discovered that it was a turtle that was about 2' long! He was creeping towards the house but unfortunately, it was raining and he didn't get close enough to get a good picture. If it hadn't been pouring, I definitely would've gone outside for a closer look. He didn't have hair, so I was tempted to lure him in and keep him as a pet. I was pretty sure by looking at him that he wasn't house broken, though, so i decided against it.