Edinburg, the Hidalgo county seat, is on U.S. Highway 281 and State Highway 107 in the south central part of the county. It is part of the McAllen, Pharr, Edinburg metropolitan area. Hidalgo, on the Rio Grande, was the original county seat. John Closner and William Briggs, who had land-development projects in the vicinity of Chapin, seventeen miles north of Hidalgo, made Chapin county seat. The townsite was named after Dennis B. Chapin, another of its promoters. Chapin's involvement in a homicide caused a change of name in 1911 to Edinburg, in honor of the birthplace in Scotland of John Young. The town grew slowly to some 800 inhabitants by 1915 and remained unincorporated until 1919. During its early years it served a ranching community, but the arrival of irrigation in 1915 initiated an agricultural economy. Edinburg quickly became a center for buying and processing cotton, grain, and citrus produce. Other economic developments before World War II included vegetable, sorghum, corn, sugarcane, and poultry (eggs) industries. After the war the economy diversified further to include peach and melon production, food-processing plants, cabinetry, oilfield equipment, concrete products, agricultural chemicals, and corrugated boxes. In the 1970s tourism increased significantly.
The first railroad service in 1909 was a spur line of eight miles, extending from the one connecting Brownsville and San Juan. Seventeen years later the city received direct rail connections with Corpus Christi and San Antonio. After highways and trucks replaced rail service, Edinburg benefitted from its location on a major highway intersection. By the 1980s the city's trucking industry numbered six commercial freight lines and two bus lines. The city has been named the "gateway city" to the Rio Grande valley.
Edinburg's first radio station started in 1947 and by 1960 served both a Spanish and English listening audience. In the 1970s and 1980s three more stations were established. An influx of people from both Mexico and various parts of the United States has given the city an ethnic and religious mix. Hispanics constitute 80 percent of the population, and well over two-thirds of them are Catholic. The Protestant influx made its first appearance with the founding of the First Baptist Church in 1912. Other Protestant denominations arrived later and included the Disciples of Christ, Lutherans, Presbyterians, Methodists, Pentecostals, Christian Scientists, Seventh-day Adventists, and the First Foursquare Church. In 1946 the Rio Grande Bible Institute started its work of training Protestant ministers for Latin America. The first Catholic church, Sacred Heart church, did not open until around 1926. Two others were added later to serve the growing Catholic population.
By tradition, Edinburg is a Democratic stronghold that reflects county politics. The governing body consists of five commissioners, including the mayor, who administers through a city manager. State institutions and agency offices in Edinburg include the Texas Department of Human Services, a Texas National Guard company, the Evins Regional Juvenile Center, the Texas Employment Commission, and the Texas Rehabilitation Commission. In 1976 the city became the home of the South Texas Symphony Association, which sponsors the Valley Symphony Orchestra, the Valley Symphony Chorale, and the South Texas Chamber Orchestra. The University of Texas–Pan American, founded in 1927 as a junior college, is in Edinburg. It had an enrollment of some 12,200 students during the academic year 1990–91, and offers both undergraduate and graduate programs. Also located in the city are Region One Educational Service Center and Edinburg Consolidated Independent School District.
The major historical landmark of Edinburg is its former city hall, erected in 1909 and located near the northwest corner of Hidalgo Plaza in front of the county courthouse. The plaza has a bust of the Mexican independence leader Padre Miguel Hidalgo y Costilla, after whom the county is named. The building, originally the county jail, has a trap door for hanging that has been used only once. Later the building became a city hall, and in 2005 it housed the county historical museum. During the late twentieth century Edinburg had an annual population growth of 3.4 percent. The 2000 population was 48,465.