According to the International Hop Growing Convention, Germany produces roughly one third of the world's hops (used as flavoring and stabilizers during beer brewing), over 80% of which are grown in the Hallertau.
Hallertau is roughly located between the cities of Ingolstadt, Kelheim, Landshut, Moosburg, Freising and Schrobenhausen.
Image:
Hopfendolde
https://www.flickr.com/photos/uwe_schubert/