How do I set the Country drop-down list to permanently hide all other countries?
Visit Admin > Site Info > Site Configuration
On the left column under Site Configuration (heading) click on Countries

Here, you can enable or disable countries to be selected.
For example: to select USA to be the only choice
- Click Select All
- Deselect only United States (US)
- Click Invert Selection – this will deselect all and reselect United States only.

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