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.

The county was established by the state legislature on March 13, 1874, and named after Thomas Green, a Confederate brigadier general.

In 1883, the town's name was officially changed to San Angelo by the United States Post Office.

Following completion of the Santa Fe Railway in September 1888, the county increased its cattle production to an estimated export of 3,500 to 5,000 railroad cars.

In 1889, San Angelo became incorporated to a city, and Fort Concho shut down after 22 years of operation.

[4] Tom Green County has a long, narrow strip of land extending to the west.

[5] During Winter Storm Uri, the city of San Angelo endured 152 hours at or below freezing temperatures.

About 30.71% of the population were Hispanic or Latino of any race, 13.2% were of German, 10.7% American, 8.2% English, and 7.2% Irish ancestry according to Census 2000.