An imaginary line dividing coastal areas from more inland areas in certain southern states in the U.S., especially the Carolinas and Georgia. The term comes from the abundance of gnats in coastal marshlands and swamps in these states and the relative lack of the insects in the inland regions.
I’m not from the piedmont. I’m just east of the gnat line.

The city has grown so big, it’s like everything north of the gnat line is considered metro Atlanta.
by kidviscious March 1, 2007
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