WARNING:
Google has disabled the API that makes this possible to lists the maps.
Visit this page for a solution. I will work to make it look better in the coming weeks.
All of Google's "My Maps" are publicly available. This link gives you a permanent URL for you to share one of your maps.
Maps can be set as either "Public" or "Unlisted", but these are not opposites.
"Unlisted" does not mean private.
"Unlisted" maps are just not searchable. But if you give the public link to someone, that person will be able to see your map, even if it is set to "Unlisted".