As far as they deem safe. Mine stay in sight of the house or what they think is their house (the human house) and almost never venture into the woods where the preds come from and try to eat them at night. They also will go down the drive way, but never to the mail box since they know better not to play chicken with the cars on the highway. However, I bet they'd go for thousands of feet if they felt safe. So the inconclusive answer i have is that they will go as far as they deem safe.