Create a sortable state column with state dropdown using simple locator data.

simple-locator-post-column-filters.php

/**
* Set the Location Columns
* @param array $columns
*/
function locationColumns($columns)
{
	$columns['wpsl_state'] = 'State';
	return $columns;
}
add_filter('manage_edit-location_columns', 'locationColumns');

/**
* Set the Custom Sortable Columns
* @param array $columns
*/
function setSortableLocationColumns($columns)
{
	$columns['wpsl_state'] = 'State';
	return $columns;
}
add_filter('manage_edit-location_sortable_columns', 'setSortableLocationColumns');

/**
* Custom Column Data
*/
function locationColumnData($column, $post_id)
{
	if ( $column !== 'wpsl_state' ) return;
	$state = get_post_meta($post_id, 'wpsl_state', true);
	echo $state;
}
add_action('manage_location_posts_custom_column', 'locationColumnData', 10, 2);

/**
* Add the State select filter to locations (Creates dropdown select menu with all states)
*/
function addStateSelect()
{
	global $typenow;
	if ( $typenow !== 'location' ) return;

	// Get all the unique states
	global $wpdb;
	$all_states = $wpdb->get_results("SELECT DISTINCT meta_value FROM $wpdb->postmeta WHERE meta_key = 'wpsl_state'");        
	$current = ( isset($_GET['wpsl_state']) ) ? $_GET['wpsl_state'] : '';
	$out = '<select name="wpsl_state">';
	$out .= '<option value="">' . __('All States', 'textdomain') . '</option>';
	foreach ( $all_states as $state ){
		$out .= '<option value="' . $state->meta_value . '"';
		if ( $state->meta_value == $current ) $out .= ' selected';
		$out .= '>' . $state->meta_value . '</option>';
	}
	$out .= '</select>';
	echo $out;
}
add_action('restrict_manage_posts', 'addStateSelect');

/**
* Add the State Filter to the Posts
*/
function addStateFilter($query)
{
	global $typenow;
	if ( !is_admin() && !is_main_query() ) return;
	if ( $typenow !== 'location' ) return;
	if ( !isset($_GET['wpsl_state']) ) return;
	
	$query->set('meta_key', 'wpsl_state');
	$query->set('meta_value', sanitize_text_field($_GET['wpsl_state']));
}
add_action( 'pre_get_posts', 'addStateFilter' );