Limit by cities.

Hi q-styler.

Sorry for my english

I has the same trouble, you can solve this in this way:

– First Remove the City input box from the form

add_filter( 'woocommerce_checkout_fields' , 'override_checkout_fields' );

// Our hooked in function - $fields is passed via the filter!
function override_checkout_fields( $fields ) {
     unset($fields['billing']['billing_city']);
     unset($fields['shipping']['shipping_city']);
     return $fields;
}

– Second, make your own box with options

add_filter( 'woocommerce_checkout_fields' , 'custom_override_checkout_fields' );

// Our hooked in function - $fields is passed via the filter!
function custom_override_checkout_fields( $fields ) {
     $fields['billing']['billing_ciudad']= array(
    'type' => 'select',
    'label'     => __('Ciudad', 'woocommerce'),
    'placeholder'   => _x('San Salvador', 'placeholder', 'woocommerce'),
    'required'  => true,
    'class'     => array('form-row-wide'),
    'clear'     => true,
     );
     $fields['billing']['billing_ciudad']['options'] = array(
     	'option_1' => 'Col. Escalon',
  		'option_2' => 'Otro ciudad o colonia'
     	);
     return $fields;
}

You can see more on documentation:

Here