Over the past several centuries, there have always been places that couples could, for various reasons, run away to and get married.
In more recent times, it was because perhaps no blood test was required, or no waiting period, no age limit, or parental consent. These runaway spots are often referred to as Gretna Greens, so called because of the famous place on the Scottish border where English couples eloped after the English Clandestine Marriage Act was passed in the 18th century.
If you are looking for a record of your ancestors’ marriage, and can’t find it in the home county, you might think a bit broader, depending on where they lived. There are many cases of people marrying in unexpected places. One couple from North Carolina slipped into Clayton in North Georgia’s Rabun County to wed. A Tennessee couple married in Rossville, Georgia, in Walker County, adjacent to Catoosa County, so a researcher would need to check both courthouses for the actual record.
There's more in an article by Kenneth H. Thomas Jr. and published in the Atlanta Journal-Constitution at https://bit.ly/3wcAVbv.