It was first known as Harrisburg when settled on May 25 1867 by Noah Harris. It became something of a boom town when natural gas was found in the area in 1887. The Gas City Land Company was founded on March 21 1892 and the town of about 150 people changed its name to Gas City a few days later.
There were 2,393 households out of which 31.4% had children under the age of 18 living with them, 52.1% were married couples living together, 12.6% had a female householder with no husband present, and 31.3% were non-families. 26.8% of all households were made up of individuals and 10.9% had someone living alone who was 65 years of age or older. The average household size was 2.46 and the average family size was 2.95.
In the city the population was spread out with 25.2% under the age of 18, 8.2% from 18 to 24, 29.1% from 25 to 44, 23.8% from 45 to 64, and 13.6% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 90.2 males. For every 100 females age 18 and over, there were 84.1 males.
The median income for a household in the city was $35,940, and the median income for a family was $42,056. Males had a median income of $34,020 versus $23,482 for females. The per capita income for the city was $18,295. About 8.1% of families and 10.2% of the population were below the poverty line, including 13.8% of those under age 18 and 8.3% of those age 65 or over.