You can make any Halo Fence virtually as large as you would like it to be. One segment of a Halo Fence (the distance between two fence posts) can be as long as 10 kilometers, or 6.2 miles. If you created a fence with 20 fence posts (the maximum number allowed), and each post was the maximum allowable distance apart, your fence would accommodate about 3,156 sq. kilometers, or over 1,200 sq. miles, or 780 thousand acres. 

Minimum fence size: We recommend that any Halo Fence is at least 30 feet by 30 feet (9.1 by 9.1 meters) to give your dog ample room to roam safely.

• Please note that the Warning Area begins about 7-10 feet (2.1-3.0 meters) before the fence boundary, so you want to give your dog as much room as possible to move around without triggering the collar's Warning Feedback.
• For example, if your fence is 20x20 (6.1x6.1), and the Warning Area cuts into that area by 10 feet (3.0 meters) on each side, then you are really giving your dog only 10 feet by 10 feet (3.0 meters by 3.0 meters) to run around.
• For this reason, you should create your Halo Fences in places where your dog can have as much room to move as possible. 

We recommend that you maintain at least 20 feet of distance between your Halo Fence boundaries and the side of a structure (like your house). Because GPS tracking can naturally vary by several feet, this 15-foot (4.6 meter) buffer prevents the boundary from overlapping your house and gives your dog ample room to move around without receiving Warning Feedback.