The County Line is the edge or border of Bikini Bottom, and the entrance into a large barren desert which leads to Shell City. There is a gas station run by two hillbillies there.
In the events of The SpongeBob SquarePants Movie, SpongeBob and Patrick are driving to Shell City to retrieve King Neptune's crown. They are harassed by the hillbillies at the gas station. They cross the line and are stopped by a thug, who drives away with the Patty Wagon. SpongeBob and Patrick then continue their journey on foot through the desert.
Landforms Beyond the Line
Beyond the County Line is very dangerous. No sea creature has ever returned when crossing into the County Line. When one goes beyond the line, they will find:
A desert (with a bar full of thugs called the Thug Tug in the middle of it.)
Skeleton Road (with an "Ice Cream Stand" in the middle of it, which is really a trap by a Frogfish.)
The Monster Trench (home to hundreds of horrible, and hideous monsters.)
A valley (Between the trench and Shell City, a long road full of garbage.)
Shell City (A gift shop on land, where a cyclops, or a man in a diving suit sells dead fish.)