Canada. All of it. I've lived in Halifax, Kingston, Belleville, Picton, Peterborough, Toronto, Hamilton, St. Catharinaes, Niagara Falls, Welland, Port Colborne, Winnipeg, Calgary, Vancouver, Victoria, Parksville, Qualicum Beach and Whiskey Creek.
IMO roughly an area along the I-35 corridor from San Marcos (North of SanAntonio) to just south of the DFW metroplex. Easier if you envision it as from Austin to Waco going South to North--
Specifically I live in Killeen, one of the cool military cities with a low cost of living where higher pay can go far.
Good definition. I'm in Austin. The Hill Country (the area around Austin including Burnet, Fredericksburg, Boerne, etc) is what I consider Central Texas, but it's really much bigger. As they say...everything's bigger in TX.