The Mariana Islands Training and Testing Project (“MITT”) is a Defense Department proposal authorizing “take” – a euphemism referring to harm, harassment, and/or killing of marine mammals and threatened and endangered species – during certain military training activities in the CNMI and surrounding waters, including, most notably, live-fire exercises at and around the island of Farallon de Medinilla and on the island of Tinian. Smaller, non-live fire activities (e.g., search and rescue, disaster response) were proposed for Saipan and Rota.

MITT follows and expands on the Mariana Islands Range Complex Project (“MIRC”), a military training authorization in effect between 2010 and 2015. Specifically, MITT implemented the following changes to the prior MIRC authorization:

  • An expanded geographic area, including, among other things, additional open sea training areas and a “transit corridor” between the Marianas and Hawaii;
  • Additional types of larger training activities and increased frequency of training;
  • New weapons systems; and
  • Removal of prior training restrictions in ecologically sensitive areas.

Mitigation was an area of particular controversy. Although MITT proposed substantial increases in the area, intensity, and frequency of military training activities, it also weakened many of the mitigation measures previously put in place as part of the MIRC project.

In 2015, the Navy issued a Record of Decision approving MITT and authorizing “take” of marine mammals and threatened and endangered species for a five-year period. A supplemental seven-year take authorization – covering additional at-sea training – was approved in 2020.

Additional information about MITT can be found here.

The MITT project re-authorized military activities within the entire Mariana Islands Range Complex; it also added new open-ocean training zones, as well as a naval transit corridor linking the Marianas to Hawaii

Project Effects

Effects Identified as Potentially Significant in EIS

Impacts on marine mammals, sea turtles, and their habitats; terrestrial biological resources; invasive species; cultural resources; wetlands

Additional Areas of Concern

Potential conflicts with the Covenant; inconsistency with coastal plans; mitigation proposals vague and inadequate; impacts on Tinian public services and infrastructure; access restrictions on Tinian and FDM.

Timeline of activities

The following timeline pinpoints important milestones for U.S. military operations and proposals in the CNMI. As shown, the U.S. military has been a part of CNMI culture and economy for many decades.


The Covenant establishing the CNMI as a U.S. Commonwealth was signed by negotiators on February 15, 1975. Section 803 required that a separate Technical Agreement Regarding Use of Land To Be Leased by the United States in the Northern Mariana Islands be executed simultaneously with the Covenant.


U.S. Department of Defense, Military Training in the Marianas Final Environmental Impact Statement and Record of Decision (June 1999)


Joint Region Marianas (JRM) was established in accordance with congressional legislation implementing the recommendations of the 2005 Base Realignment and Closure Commission.


Mariana Islands Range Complex Final Environmental Impact Statement/Overseas Environmental Impact Statement, published May 2010.

The Quadrennial Defense Review (QDR) evaluated global U.S. military strategy and priorities (Department of Defense 2010,, and called for development of additional training capabilities for unit, combined, and joint forces in the Western Pacific.

Guam and CNMI Military Relocation Final Environmental Impact Statement: Relocating Marines from Okinawa, Visiting Aircraft Carrier Berthing, and Army Air and Missile Defense Task Force Volume 3, published in July 2010


Training Needs Assessment: An Assessment of Current Training Ranges and Supporting Facilities in the U.S. Pacific Command Area of Responsibility (hereafter the “Assessment”) identified and validated unfilled training requirements for units/commands in the U.S. Pacific Command Area of Responsibility (Department of the , 2013,


Mariana Islands Range Complex Airspace Environmental Assessment/Overseas Environmental Assessment, published in June 2013.


The 2014 QDR confirmed the U.S. military’s continued commitment to rebalance the Asia-Pacific region, which is increasingly central to U.S. political, economic and security interests.


Record of Decision for the Final Supplemental Environmental Impact Statement for Guam and Commonwealth of the Northern Mariana Islands Military Relocation


U.S. Air Force (USAF) Tinian Divert Infrastructure Improvements Supplemental Environmental Impact Statement (SEIS)

Mariana Islands Training and Testing SEIS/Overseas EIS, published June 2020

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