Users can manage to create, edit and delete the territories when needed.These are setup to associate them to a specific customer please refer to Customer Account "Advanced" Setup.
Instructions
Follow these steps:
Go to Setup > Settings > Customers.
Click on the "Territories" link.
The Customer Territories window will pop up, click on "Add new territory" link.
Enter the "Territory Name", by default this will be Active, if needed you can deactivate the option by checking off the box.
Click on Save.
The new territory will be displayed as shown below:
Under the Actions column, you can Edit or Delete the territory if needed.