Also spelled "The Booneys," this catchy saying is used to describe something in the middle of nowhere or something in a country, farm, or hick-town-like location.
Pamela: I almost couldn't find Starbucks; My GPS couldn't even find it.
Lisa: I know, that Starbucks is out in the Boonies!
Is basically a high ride, driving around in the middle of the woods and farmland smoking weed for miles. Being stoned and trying to find your way back to where you came from on narrow gravel roads in the middle of nowhere, for fun.