he "US only" item location filter selects items that are listed as being in the United States; however, as you have likely seen, not every seller that lists items in the US ships from the US as they should.
Before ordering you should check the estimated delivery dates -- that is usually a good indication of how far away items actually ship from. Also, going to a seller's profile page or feedback page will tell you where the seller's account is currently registered; if you go to the seller's current listings ("items for sale") and scroll down on the left side of the page, under "Seller information" you can check where the account was originally registered, I believe.
Although some overseas sellers do use US warehouses to ship their items (and some US-registered sellers may employ overseas drop-shippers), if a seller is registered overseas, that raises the likelihood of an item shipping from outside the US, particularly for multiple quantity commodity items. Checking seller feedback will often reveal if there are problems with long shipping times, canceled orders or other supply chain warning signs.
In the US at least, when faced with a long list of search results that you want to narrow down to sellers that can ship quickly, using the "Guaranteed Delivery" filter will often help; very few sellers that ship from overseas qualify. That is a rough filter, though -- many domestic sellers may be filtered out as well.
If no sellers can deliver to your area in four days, try changing your zip code and searching again -- the trick is to find sellers that can reliably deliver somewhere in the US in four days; the actual delivery time to your location is not material as long as it filters out overseas sellers. Just be sure to change your zip code back before you place an order to see the correct shipping calculations.
