It’s an Eastern Rat Snake.
https://www.nwf.org/Educational-Resources/Wildlife-Guide/Reptiles/Black-Rat-Snake
Great ratters & mousers. Very good at getting into chicken coops & eating eggs. My SIL saw one that had caught a baby bunny & was constricting it to death. The only time I would kill them was when I found one in the chicken coop - you can remove them & they just come back. We had one in the coop with a scar on its back so identifiable - SIL took it down the road & it was back & headed for the coop 3 days later.
Funny story - we have a lake cabin that is very rustic. It is not a 4-season house - family uses it late spring to late fall until the water needs to be turned off. There are always mice over the winter. My brother was making coffee one morning when a movement on the counter caught his eye - it was a Rat snake, coming out from behind the microwave! It had found a way in the house to hunt mice. If my SIL or some of the other women guests had seen that snake first, there probably would have been a ‘scream fest’ & potentially some fainting. My brother wrangled the snake into a trash can (a 3 footer so not a huge snake) & released it. He took pics to show the ladies, who were horrified :-)
That’s a really dark one. Maybe it’s just how the pic came out. I had a couple Black Rat Snakes as pets* at one time or another when I was a kid, but not so dark. Or... maybe that was / is a local variation of many of ours.
*I have a couple pretty good accounts about my pet snakes getting loose in the house. I’ll tell them here later if I get some time. My light fixture replacement ended up being a bit more involved than expected...
My daughter reminded me that “central” Black Rat Snakes are usually darker in the north part of their range, and lighter in the south, with more of a pattern evident in the south. Since we are “mid-South”, a bit lighter would not be unusual.