Tom Green County has a long, narrow strip of land extending to the west. In 1889, San Angelo became incorporated to a city, and the Fort Concho shut down after 22 years of operation. Following completion of the Santa Fe Railway in September 1888, the county has increase its cattle production to an estimated export of 3,500 to 5,000 railroad cars. In 1883, the town's name was officially changed to San Angelo by the United States Post Office. The county seat was moved to Santa Angela. In 1882, flood waters of the Concho River destroyed the town and drowned 65 people. The original county seat was the town of Ben Ficklin. It originally comprised an area over 60,000 sq mi (160,000 km 2). The county was established by the state legislature on March 13, 1874, and named after Thomas Green, a Confederate brigadier general. Tom Green County is included in the San Angelo metropolitan statistical area the county is home to Goodfellow Air Force Base, as well as Angelo State University, part of the Texas Tech University System.

It is named for Thomas Green, who was a Confederate soldier and lawyer. The county was created in 1874 and organized the following year. As of the 2020 census, its population was 120,003. Tom Green County is a county located on the Edwards Plateau in the U.S. Brown Justice Center across from the Tom Green County Courthouse

Tom green jail log