New Harmony
From Halopedia, the Halo wiki
New Harmony was a UNSC colony world. It may or may not have been related to Harmony, another UNSC colony.
In 2537, a well known battle occured at New Harmony between UNSC and Covenant forces, the Battle of New Harmony, which Vice Admiral Danforth Whitcomb participated in. The UNSC forces had up to 57 ships, therefore defeating the Covenant but taking heavy casualties.
