Google Map is awesome plugin to add Google Custom map in website.It is fully customizable and can be use as shortcode. It is usable using widget and has all possible options to customize.
Demo Link: http://srmilon.com/wp/blog/2015/02/21/google-map-demo/
Google Map plugin URL: https://wordpress.org/plugins/wp-gmap/
To get Latitude and Longtitude: http://www.latlong.net
If you get any problem to install just comment here