I can't say I have ever seen anything like Gummo IRL but then again I live in the area of one of the main cities, and I have no doubts that shit gets that awful in small towns with high rates of meth addiction.
Probably the closest thing is that on the highway between Cincinnati and Columbus, there are two notable landmarks, one being a farmhouse that has a conferederate flag painted on the roof and a suspiciously-burned-looking giant cross in his yard, and a farm field next to the highway that has billboards with bible verses and "HELL IS REAL" written on them in it.
There's also the King of Kings
statue in front of a megachurch near Monroe, which is more commonly referred to as "big butter jesus" or "touchdown jesus", and later caught fire and burned down when it got hit by lightning (the church did not take this as a sign of divine intervention). They built a new one in its place, but it's a generic "give me a hug" jesus and is not nearly as interesting or funny.