Yeah, it's a grey rat snake.
I spent forever where I used to live trying to find some and one crawls into your house? I hate you! j/k
Unfortunately when I found a place where they did reside (I was just observing, not catching them) they started working on the road there and I never saw them again. The road work included tearing up most of the land on each side, so I guess they destroyed a lot of their territory and the snakes moved much further into the woods.
BTW, it's really not hard for a snake to find their way into your house. For all you know you had several babies somewhere in your house. A lot of the time they get in through holes that mice make and stuff, otherwise they just find other open spaces. Not hard for something that slithers along that ground and spends their time looking for that kind of stuff.