The UN Marine Corps was one of the main combat groups in the Interplanetary War. In 2163, Marines were first deployed outside of Earth on Mars. After the UN won the war in 2164, it transitioned into the UNSC, with the UN Marines becoming the UNSC Marine Corps.
- It is possible that most of the traditions of the UNMC, which were probably a coalition of various Earth Marine Corps (especially the United States Marine Corps) before that, were carried on to the UNSC Marine Corps.
- It was in the era of the Continental Marines that the nickname "Leatherneck" was adopted. The Marines would wear leather collars to provide protection from garroting, and attacks directed at their necks as they boarded enemy ships, a hazardous and unpredictable combat environment.
- United Nations
- United Nations Space Command
- Interplanetary War