Where in North America is area code 210?

Area codes 214, 972, and 469 serve Dallas, Texas, and suburbs:

Dallas, Addison, Allen, Anna, Avalon, Balch Springs, Bardwell, Blue Ridge, Carrollton, Cedar Hill, Celina, Copeville, Crandall, Desoto, Duncanville, Elmo, Ennis, Farmersville, Fate, Ferris, Flower Mound, Forney, Forreston, Frisco, Garland, Grand Prairie, Hutchins, Irving, Italy, Josephine, Kaufman, Lancaster, Lavon, Lewisville, Little Elm, Maypearl, McKinney, Melissa, Mesquite, Midlothian, Milford, Nevada, Palmer, Plano, Princeton, Prosper, Red Oak, Rice, Richardson, Rockwall, Rosser, Rowlett, Royse City, Sachse, Scurry, Seagoville, Sunnyvale, Terrell, The Colony, Venus, Waxahachie, Westminster, Weston, Wilmer, Wylie