MBP Location incorrect: How to change?

I bought my MBP used a few years ago and the Location always shows my computer in the area in which I bought it - presumably, where the owner lived.

How do I change this? I went to Security and Privacy to the Locations tab but I can't figure out how to change it to my zip code.

 

If I go to a online store - say "The Home Depot" - and look up an item, it will say that item is available at a store that is not near me but based in the location in which I bought the computer. It's basing that store on my location.

If I click "use my location" in the browser on that page, it uses that same zip code/location.

If I type in my zip and click "make this my store," it will work until I close and reopen the browser and it goes back to the default location.

This location is about 15-20 miles away from me. So I'm not sure if the location service is just screwy, or if something on the computer is still tired to the previous owner's account. I've done a factory reinstall of Mountain Lion - now recently upgraded to El Capistan, and I'm still experiencing this issue.