woocommerce_countries_shipping_country_states filter-hook . WC 1.0

Usage

add_filter( 'woocommerce_countries_shipping_country_states', 'filter_function_name_1823' );
function filter_function_name_1823( $states ){
	// filter...

	return $states;
}

$states

-

Where the hook is called

return apply_filters( 'woocommerce_countries_shipping_country_states', $states );

Where in WP core the hook is used WooCommerce