Odem is at the intersection of two rail lines twenty miles from Corpus Christi in southwestern San Patricio County. The St. Louis, Brownsville and Mexico Railway laid tracks through the county in 1907, and the town was platted in 1909 by John James Welder and David Odem. It was named for Odem, who was the county sheriff. A switch and siding at the site was known as Dofin, and a mail hook was set up even before the post office was approved. The post office opened in 1909 with Jarrad B. Clark as postmaster. The town developers sold farmland from the Brazado Pasture, which was once part of the Coleman-Fulton Pasture Company lands. The development of this ranchland into farms, plus the absorption of the nearby small communities of Meansville, Angelita, Kaleta, and Sharpsburg, helped Odem grow as a trading center. The Odem State Bank opened in 1914, and by 1915 the town had a population of 500 and three churches, several general merchandise stores, and a growing school system. The Odem News, with J. C. Price as editor, began publication on April 1, 1915. An Odem chamber of commerce was organized in 1928, and the town was incorporated in 1929, with J. F. Janicke as mayor. The aldermanic form of government was adopted in 1933.
The local economy initially depended on growing vegetables for commercial markets. In the early 1930s A. R. Lee operated the Pioneer Cannery, which produced Del Mar brand vegetables. In the fall of 1930 an entire trainload of radishes moved from the Las Palmas Farms, owned by E. C. Caldwell, to northern markets. During the season, up to twelve cars of radishes a day left Odem. Onions, cabbage, carrots, beets, and spinach were shipped out of the Odem sheds. By the 1980s cotton, corn, and grain sorghum (see SORGHUM CULTURE) had supplanted vegetables. At that time Odem supported a large grain elevator, and three gins were located within a few miles of the city. Oil, first discovered in the area during the 1930s, diversified the local economy. During the 1980s many Odem residents worked in nearby Corpus Christi. Growth in the outlying rural areas, as well as urban development, pushed the town's estimated population to nearly 3,000 by 1988, when it had thirty-six rated businesses. In 1990 the population of Odem was reported as 2,366. By 2000 the population was 2,499.