Boundaries are virtual geo-fences you can create that trigger an alert when crossed. Only you see the alert. You can create as many as you wish.
To create a boundary, on any map screen, just tap where you want to create the boundary. Simply give the boundary a name, and select from 25ft up to 100mi and a radius around the point on the map you selected will be shown. To remove or edit the boundary, just tap tap it again.
You can manage all of your boundaries from the boundaries and pins section of the app.