Heath is on Farm Road 740 seven miles south of Rockwall in southwestern Rockwall County. It was named for John O. Heath, who in 1846 became one of the earliest settlers in the area. The settlement was originally known as Black Hill—a reference to the black soil of the area—and received a post office, the first in what is now Rockwall County, in 1849. In 1854 the post office was moved to nearby Rockwall. From this time until 1886 the settlement was known as Willow Springs, after a local stream. In 1886 the name became Heath, and the town again received a post office, which operated until 1906.
Heath grew slowly during the 1880s and 1890s. In 1892 it had a population of seventy-five and five businesses. By 1898 a one-room school served fifty-six students. By 1902 businesses included four cotton gins, and the Heath Independent School District had been established. By 1904 the population reached 225. In 1916 a fire destroyed a number of the community's buildings. This event marked the beginning of a long period of decline, as the Great Depression drove many residents to nearby cities in search of jobs. By 1936 the population of Heath had declined to 150, and only five businesses remained in operation. By 1950 the school district had merged with that of Rockwall, and the local school was closed. The population stood at fifty.
After 1950 Heath grew steadily, partly because of the growth of the nearby Rockwall and Dallas-area cities and the development of Lake Ray Hubbard just west of the community in 1969–70. Heath was incorporated in 1959. The population increased from 175 in 1960 to 449 in 1970. By 1980 the population was 1,459, and it was estimated at 1,647 in 1988. Although some grain and cotton farming continued in the area in the late 1980s, Heath had once again begun to develop a business and professional community. In 1990 the population was 2,108, and in 2000 the community had 4,149 inhabitants.