<?php
add_filter( 'display_post_states', 'wpmudev_add_post_state', 10, 2 );
function wpmudev_add_post_state( $states, $post ) {
	if( $post->post_name == 'contact' ) { //Slug of the page, this should be unique
		$states[] = 'Contact Page';
	}
	return $states;
}