John, I would guess if there are that many bees around, either someone around you has a hive or there is one that has moved into a tree/log/other space nearby. They can travel up to a couple of miles if they find a good source of nectar, they usually don't go that far if there are good sources near them, but they can. My husband is a beekeeper. I don't do anything with them, but they are fascinating to watch.
If you are interested in starting, you can call your county Extension office. They should be able to put you in contact with someone who can help. If we were closer, my husband would be thrilled to help you. He started it as a hobby and it has grown tremendously; he has about 40 hives now (in different locations), has started a beekeeping association for our county, and is the hive inspector for our county.