It's located 2,100 miles south of North Korea and 4,000 miles west of Hawaii.
In addition to the military presence, Guam also relies heavily on tourism to boost its economy, attracting more than 1.5 million visitors drawn to its pristine beaches and luxury resorts in 2016.
Guam is home to U.S. Naval Base Guam and the Andersen Air Force Base. The chilling two-page fact sheet details what citizens of the 162,000-populated island that houses 6,000 USA troops should do to survive the worst outcome of the boiling tensions between Washington and Pyongyang.
That puts its total population of 170,000 in range of the Hwasong-12 intermediate-range ballistic missiles that Kim Jong Un's regime has threatened to fire as a counter-punch to President Donald Trump's warning that the US would respond with "fire and fury" to provocative actions by North Korea. It has limited self-government, with a popularly elected governor, small legislature, and non-voting delegate in the U.S. House of Representatives.
The U.S. -made Patriot batteries aren't the only pieces of high-tech American military gear in Japan that will have its ears perked up.
Guam Governor Eddie Calvo said the remote Pacific island was accustomed to being a target ever since Washington placed military installations there.
While experts estimate the consequences and economic impact of an imminent USA vs North Korea war, some Guamanians are stockpiling essentials to survive while taking shelter if Pyongyang makes good on its promise to strike the island.
"I don't see a military solution and I don't think it's called for", said German Chancellor Angela Merkel.
This is the first time Park can recall North Korea publicly and explicitly threatening Guam. North Korea has been at odds with the United States since the USA backed South Korea during the Korean War.
Altogether, 7,000 US military personnel are stationed on Guam.
The U.S. took control of Guam in 1898, when Spanish authorities surrendered to the U.S. Navy.
In October 2006, an unofficial spokesman for North Korea in Japan told ABC Radio Australia that Guam, Japan and Hawaii were potential targets if the United Nations levied tougher sanctions against North Korea. Residents do not pay USA income taxes or vote in the general election for US president. And at the southern end, there's the Naval Base Guam that hosts the Submarine Squadron Fifteen and the USS Frank Cable. Guam was also a refueling and transfer spot for people heading to Southeast Asia, and many refugees fleeing Saigon were evacuated through Guam.
It comes as cracks between the two countries allegiance seem to have appeared as the row between North Korea and the U.S. threatens to spill over into military action between the two nuclear powers. Chamorros are the indigenous people of Guam.
The exercises were scheduled well before tensions began to rise over Trump's increasingly fiery rhetoric and North Korea's announcement of the missile plan, which if carried out would be its most provocative launch yet. It did so to compensate for USA forces diverted from other bases in the Asia-Pacific region to fight in the Middle East.
McAvoy reported from Honolulu.