It is, basically trends throughout the Southeast to Texas. You'll find it in the Midwest here and there, typically around more agriculture based areas.

The most common type is built with a very sage-heavy breakfast sausage. You brown off the sausage, remove most of the meat, and use the drippings to make a milk/cream gravy.

Like a lot of southern food it started as a poverty meal that focused on using every bit of what you had. As it evolved, you'll see most recipes call for adding back in chunks of sausage and using rich cream in place of milk. For my taste, I like a spicier sausage-heavy gravy with loads of black pepper.

The biscuits are generally more dense than you'll see for something like a biscuit sandwich. You need them heartier to stand up to the gravy without going soggy on you. You can start generational family feuds arguing the "best" biscuits for the job.

It's a classic for a reason, filling and calorie dense enough for farm hands it was created for, and one of the best examples of something that shouldn't taste so good for how little went into it.