Set

states.php

<?php
/**
 * Sell only in specific states
 */
add_filter( 'woocommerce_states', 'wc_sell_only_states' );
function wc_sell_only_states( $states )
{
    $states['US'] = [
        'AL' => __( 'Alabama', 'woocommerce' ),
        'AK' => __( 'Alaska', 'woocommerce' ),
        'AZ' => __( 'Arizona', 'woocommerce' ),
        'AR' => __( 'Arkansas', 'woocommerce' ),
        'CA' => __( 'California', 'woocommerce' ),
        'CO' => __( 'Colorado', 'woocommerce' ),
        'CT' => __( 'Connecticut', 'woocommerce' ),
        'DE' => __( 'Delaware', 'woocommerce' ),
        'DC' => __( 'District Of Columbia', 'woocommerce' ),
        'FL' => __( 'Florida', 'woocommerce' ),
        'GA' => _x( 'Georgia', 'US state of Georgia', 'woocommerce' ),
        'HI' => __( 'Hawaii', 'woocommerce' ),
        'ID' => __( 'Idaho', 'woocommerce' ),
        'IL' => __( 'Illinois', 'woocommerce' ),
        'IN' => __( 'Indiana', 'woocommerce' ),
        'IA' => __( 'Iowa', 'woocommerce' ),
        'KS' => __( 'Kansas', 'woocommerce' ),
        'KY' => __( 'Kentucky', 'woocommerce' ),
        'LA' => __( 'Louisiana', 'woocommerce' ),
        'ME' => __( 'Maine', 'woocommerce' ),
        'MD' => __( 'Maryland', 'woocommerce' ),
        'MA' => __( 'Massachusetts', 'woocommerce' ),
        'MI' => __( 'Michigan', 'woocommerce' ),
        'MN' => __( 'Minnesota', 'woocommerce' ),
        'MS' => __( 'Mississippi', 'woocommerce' ),
        'MO' => __( 'Missouri', 'woocommerce' ),
        'MT' => __( 'Montana', 'woocommerce' ),
        'NE' => __( 'Nebraska', 'woocommerce' ),
        'NV' => __( 'Nevada', 'woocommerce' ),
        'NH' => __( 'New Hampshire', 'woocommerce' ),
        'NJ' => __( 'New Jersey', 'woocommerce' ),
        'NM' => __( 'New Mexico', 'woocommerce' ),
        'NY' => __( 'New York', 'woocommerce' ),
        'NC' => __( 'North Carolina', 'woocommerce' ),
        'ND' => __( 'North Dakota', 'woocommerce' ),
        'OH' => __( 'Ohio', 'woocommerce' ),
        'OK' => __( 'Oklahoma', 'woocommerce' ),
        'OR' => __( 'Oregon', 'woocommerce' ),
        'PA' => __( 'Pennsylvania', 'woocommerce' ),
        'RI' => __( 'Rhode Island', 'woocommerce' ),
        'SC' => __( 'South Carolina', 'woocommerce' ),
        'SD' => __( 'South Dakota', 'woocommerce' ),
        'TN' => __( 'Tennessee', 'woocommerce' ),
        'TX' => __( 'Texas', 'woocommerce' ),
        'UT' => __( 'Utah', 'woocommerce' ),
        'VT' => __( 'Vermont', 'woocommerce' ),
        'VA' => __( 'Virginia', 'woocommerce' ),
        'WA' => __( 'Washington', 'woocommerce' ),
        'WV' => __( 'West Virginia', 'woocommerce' ),
        'WI' => __( 'Wisconsin', 'woocommerce' ),
        'WY' => __( 'Wyoming', 'woocommerce' ),
        'AA' => __( 'Armed Forces (AA)', 'woocommerce' ),
        'AE' => __( 'Armed Forces (AE)', 'woocommerce' ),
        'AP' => __( 'Armed Forces (AP)', 'woocommerce' ),
        'AS' => __( 'American Samoa', 'woocommerce' ),
        'GU' => __( 'Guam', 'woocommerce' ),
        'MP' => __( 'Northern Mariana Islands', 'woocommerce' ),
        'PR' => __( 'Puerto Rico', 'woocommerce' ),
        'UM' => __( 'US Minor Outlying Islands', 'woocommerce' ),
        'VI' => __( 'US Virgin Islands', 'woocommerce' ),
    );

    return $states;
}