NULL Of 254 counties in the Lone Star State, Rockwall County is 254th in terms of its size (148 square miles). Rockwall County is in Dallas Prairie Texas. Texas's Rockwall County has about 1,000 acres of equestrian property for sale based on recent Land Network data. The combined market value of land and rural real estate for sale here was nearly $14 million. Browse all Rockwall County horse farms for sale on the Land Network to find the equestrian property that's right for your future needs, whether you're a horse breeder, equestrian business or simply horse lover looking for stable facilities, grooming pens or grazing pasture for your own horses. The most common type of land for sale by combined acreage in Rockwall County is residential property.