[4] The city is an agricultural community on Comanche Creek southwest of Mason Mountain, on the Edwards Plateau and part of the Llano Uplift.

George W. Todd established a Fort Mason post office March 8, 1858, which became consigned to the civilian settlement on June 26, 1858.

[7] After the Civil War, returning Confederate veterans and German ranchers clashed in 1875 over cattle rustling and other crimes.

In the midst of the war, Loyal Valley homeowner Tim Williamson[8] was murdered by a dozen masked vigilantes, who accused him of cattle theft.

Williamson's adopted son, Texas Ranger Scott Cooley,[8] sought revenge.

Cooley and his desperadoes, which included Johnny Ringo,[9] created a reign of terror over the area.

[16] The Broad Street Bridge, a reinforced-concrete truss and the only one of its kind in Texas, was built across the Comanche Creek in 1918.

[17][18] According to the United States Census Bureau, the city has a total area of 3.7 square miles (9.5 km2), all land.

The largest gem-quality topaz found in North America came from Mason County,[19] weighing almost 3 lb (1.4 kg).

[20] Mason experiences a humid subtropical climate, with hot summers and a generally mild winter.