Royse City is a city in Rockwall County in the U.S. state of Texas. It also extends into Collin and Hunt counties. The population was 2,957 at t…Royse City is a city in Rockwall County in the U.S. state of Texas. It also extends into Collin and Hunt counties. The population was 2,957 at the 2000 census, rising to 9,349 in 2010. The estimated population in 2018 was 12,998. In 2020, its population grew to 13,508.