Southern Comfort Liqueur is term variably a flavored whiskey or a liqueur, often depending upon the proof, which can come from 100 all the way down to 40. We have opted to list it at 70 proof as the most common spirit available in the United States. It is produced in Kentucky by Brown Forman, who also own the label (some of the filings with the federal Tax and Trade Bureau suggest some of the production is shared by Jack Daniels).
Southern Comfort is the oldest whiskey liqueur available on the market flavored with peaches and other citrus flavors. As a sweeter, softer product it has become popular in numerous mixed drinks. It was originally produced in 1850 by Irish-born M.W. Heron in New Orleans. His original intent was to make rougher whiskeys coming down river from Tennessee and Kentucky more palatable. He did this by flavoring it with fruit and other flavorings--the birth of "Soco."
The brand was sold by Brown Forman to Louisiana-based Sazerac in 2016 as part of a $543.5 million deal.