A new Google Maps-based web app has placemarks for major locations mentioned in hip hop lyrics, plus the inside story behind each place and the song that named it.

It’s called “The Rap Map,” and its database is by far strongest in New York City. That’s partly because New York City is an important locale in hip hop history, but we have to admit we’re a little disappointed with the volume of entries for Los Angeles and Chicago, two other cities with incredible histories documented in rap music.

That said, the map is less than a week old and users can suggest locations, so the entries will probably expand in the future.

The app was created by Rap Genius, a website dedicated to the history, meanings and stories embedded in hip hop song lyrics. It’s a natural extension for the website’s mission, of course, and just another neat example of how web apps like Google Maps and the developer tools that come with them can be used creatively.

In the past, we’ve seen Google Maps used to aggregate Foursquare and Gowalla checkins together, help people find flu shots, map Twitter trends, show apartment listings and even help the people of Iran find embassies accepting injured people. Those are just a few examples of many, of course.

Thanks to MASHABLE.com for this story