Thank you for reaching out to the Community! I'm happy to provide some assistance with adjusting your shipping settings, to ensure this gets resolved.
To provide some insight, shipping zones are what determines the countries and/or regions that customers can purchase from. To restrict the shop to customers within the United States, you will need to update this zone from within the Shopify admin. To achieve this, you can:
Head to Settings > Shipping and delivery, from the Shopify admin.
Next to the shipping profile where you want to edit a zone, clickManage.
Next to the zone that you want to edit, click the...button.
In the drop-down menu, clickEdit zone.
In the Search countries and regions section, un-select all countries except the United States. ClickDone.
Once successfully completed, you can confirm these changes have been applied by placing a test order. The checkout page should display only the United States as the available country to ship to. For more information on this, you can check out our Setting Up Shipping Zones documentation as it touches on this further.
Please let me know if you have any other questions or concerns.
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