If you want all your searches to be limited to a "US only" item location by default, there is a way to accomplish this.
If you use the eBay app, you can do this by first enabling "Lockable Filters" in the Filter Customize menu. Then, select an item location filter option and you should see a lock icon appear. Tap the lock icon so it turns blue and locks to set that as your default search option. From then, all your searches should include that filter option until you unlock or change it.
Using a browser, the lockable filter option is not available. But if you use certain desktop browsers, you may be able to use a third party browser add-on called "eBay item location -- my country only" which allows you to override eBay's "default" item location setting.
Note that when searching, if a US-only search finds few results, eBay may provide additional results after the formal search results, showing additional items available from international sellers. If you are scrolling quickly, you may miss the delineation between the two sections.
