That part of South Carolina is called "The Dark Corner?" I never heard that expression. I spend a lot of time in that area, going from Marshall NC to visit relatives in Georgia. I love to drive Highway 11, through Pumpkintown etc.
Also, I drove the big rig out of Hwy 101 in Greer for 8 years. On my drive down from Marshall I always stopped at the Ingles in Landrum to stock up on food for 2 weeks.
There's a lot of terminals near Greenville, I spent countless hours at the BMW plant in Greer, also at the many Michelin plants in Greenville/Spartanburg/Sandy Springs.
Never heard it called The Dark Corner.
Oh yeah .... there is a small contingent of special stupid in that area that goes-back to Revolutionary War times. Some of the finest old school country people you will ever meet ... and some of the worst.
Every state has them in pockets.
Memphis, Tennessee, Baltimore Maryland and then out in that county on Live PD, Salt Lake City with the Mormans, parts of Michigan, a lot of places in Ohio, almost all of Southern and parts of central California, Atlanta, Pennsylvania .... parts of Texas. West Virginia has some really dark places.
It's not just a SC thing by any stretch of the imagination.
But yeah, The Dark Corner in SC ... you don't wanna get lost up in there at night.