Gas is a city in Allen County, Kansas, United States. As of the 2020 census, the population of the city was 475. The city was named for the abundant natural gas that was found in the area.

Allen County is a county located in the southeast portion of the U.S. state of Kansas. Its county seat and most populous city is Iola. As of the 2020 census, the population was 12,526. The county was named for William Allen, a U.S. Senator from Ohio and prominent supporter of westward expansion.