Union County, South Carolina is located in the northeastern corner of Upstate South Carolina's defined region, bordered by Spartanburg and Cherokee counties to the north, Chester County to the east, Newberry and Laurens counties to the south, and Laurens County to the southwest. The county seat, Union, is a traditional Piedmont mill town located at the convergence of US-176 and SC-49.

Union County is one of the more rural and sparsely populated counties in Upstate SC. The county's economy has historically been tied to textile manufacturing, and while the county has diversified, it remains a working-class community with a predominantly rural road network and limited traffic control infrastructure outside of the Union city limits.

US-176 is the primary north-south corridor connecting Union County to Spartanburg to the north and to Columbia and the Midlands via I-26 to the south. SC-9 runs east-west through northern Union County, connecting to Cherokee County (west) and Chester County (east). These two routes carry the majority of inter-county traffic and generate the highest crash frequency in the county.

Wallace Thomson Hospital (now MUSC Health Union) is the county's sole acute care facility. Its limited trauma capability means that serious crash cases from Union County are transported to Spartanburg Medical Center (Level I trauma) in Spartanburg, approximately 30–35 minutes north via US-176.

South Carolina's modified comparative fault rule applies throughout Union County. Recovery is available as long as the injured party is found less than 51% at fault. Punitive damages are available for reckless or willful conduct.