Dogs who like to explore the neighborhood are putting themselves in danger. A dog that roams risks being hit by a car, fighting with other dogs or being picked up by animal control. Some dogs have an affinity for roaming, but making some lifestyle changes can help curtail his desires. No matter how reliable your dog is at staying home, he should always wear a collar with an identification tag that has your current address and phone number.
Neuter your dog, if he isn't already. Intact male dogs are much more likely to roam than neutered males or females. An intact male that leaves home also has the ability to contribute to the pet overpopulation problem.
Install a sturdy fence around your yard. Nothing takes the place of a physical barrier in keeping your pet on your property. It isn't full-proof, but a solid wood or chain-link fence is often a more effective barrier than electric and invisible options.
Exercise your dog daily. Don't make the mistake of thinking a large fenced backyard is a substitute for regular exercise. Regular walks, games of fetch and other aerobic activities help your dog burn off excess energy, making him less likely to roam.
Invest time in your relationship. Aside from time spent exercising your pup, spend time grooming him, let him hang out in the house with you and generally make him part of the family. If your dog lives by himself in the yard, with little interaction from others, he will look for a social outlet in the neighborhood.