JSFiddle - React, Tailwind, and code Playground

HTML

<select class="region">
    <option value="1">1</option>
    <option value="2">2</option>
    <option value="3">3</option>
    <option value="4">4</option>
    <option value="5">5</option>
</select>

JavaScript

$(function() {
    var region = localStorage.getItem('region');
    
    if (region !== null) {
        $('select.region').val(region);
    }
    
    $('select.region').on('change', function() {
        var selected_region = $(this).val();
        
        localStorage.setItem('region', selected_region);
    });
});