If you check the list of PBS member stations/networks, you'll notice that a good chunk of the Southeastern US (or south of the Ohio River) all have statewide networks--Kentucky, West Virginia, Maryland, North Carolina, South Carolina, Georgia, Alabama, Mississippi, Arkansas, and Louisiana. Tennessee's PBS member stations are all community-owned entities in the individual regions they serve, although the state's Department of Education initially launched stations in Jackson/Martin, Chattanooga, Cookeville (serving the Nashville region) and a regional network serving the Tri-Cities and Knoxville. In Florida, the member stations there, outside of Tampa/St. Petersburg, Jacksonville, Miami/Fort Lauderdale, and West Palm Beach, are owned by the state universities/colleges, but operate independently of each other. Virginia has a regional network, one serving Richmond, Harrisonburg, and Charlottesville, and the individual member stations in the Hampton Roads (WHRO) and Roanoke/Lynchburg (WBRA) areas.
In many of these locations, they also have more than one PBS option--most notably in South Florida (WPBT/WXEL and WLRN), Atlanta (WGTV and WPBA), Hampton Roads (WHRO and PBS North Carolina's WUND), Charlotte (WTVI, WNSC [South Carolina ETV], and WUNG [PBS NC]), Jacksonville (WJCT and GPB's WXGA), Mobile/Pensacola (WSRE and APT's WEIQ), Nashville (WNPT and WCTE), Cincinnati/Northern Kentucky (WCET, WPTO, and KET), and the Baltimore-DC region (WETA, WHUT, and the Maryland and West Virginia networks).
On the other end of the spectrum...Dallas/Fort Worth, Houston, Phoenix, Detroit, Orlando, and Sacramento are the largest markets in the top-20 with only a single PBS outlet.