Secret Escape Route: Top Choice for North Korean Defectors and What it Means for Security

South Korea’s Han River Estuary Neutral Zone: A Critical Area for Defections

The Han River estuary neutral zone stretches about 67 kilometers from Manuri in Tanhyeon-myeon, Paju, Gyeonggi Province, to Bolseom-do in Seodo-myeon, Ganghwa County, Incheon. This area faces North Korea’s Kaesong City and is situated directly across from Haenam-ri in South Hwanghae Province.

Established to prevent accidental conflicts between South and North Korea, this neutral zone operates without a formal military demarcation line (MDL). It is overseen by the United Nations Command Military Armistice Commission (MAC).

A key spot within this zone is Gyo-dong Island in Ganghwa County. Located just about 2.5 kilometers from North Korea, this island sits at the northern tip of Ganghwa County. Directly across the water lies North Korea’s Hwanghae Province. The 5th Brigade of the 2nd Marine Division handles border operations in this area.

The region is notorious for frequent defection cases. It has even served as a route for defectors returning to North Korea. For example, in August 2017, a North Korean defector named Kim swam across the Han River using driftwood and Styrofoam. He later used the same route to return to North Korea in July 2020.

Gyo-dong Island and its surroundings are known for being popular escape routes for defectors. Military officials report that many defectors use the changing tides to cross the river when the water levels drop or swim across during high tides.

While much of Gyo-dong Island’s coastline is fenced, some areas where civilians live are reportedly unfenced.

Gyo-dong Island: A Frequent Route for North Korean Defectors

Gyo-dong Island has a notable history as a recurring route for North Korean defectors. In September 2012, a North Korean defector in his 20s, who had clung to a log to float to Gyo-dong Island, was apprehended after residents reported him. The following August, a defector in his 40s swam to Gyo-dong Island and identified himself as a North Korean after waking a resident.

The trend continued in August 2014 when a father and son in their 50s and 20s swam ashore and were discovered by Marine Corps sentries, who then facilitated their defection. Another defection occurred in September 2015 when a North Korean defector swam to Gyo-dong Island and successfully defected.

The most recent case occurred in the early morning of August 11, 2023. A North Korean defector in his 20s crossed into Gyo-dong Island and defected. The Marine Corps sentry on duty used thermal imaging equipment (TOD) to detect and guide him safely. This was the first defection via Gyo-dong Island since 2017, when a defector named Kim later re-defected to North Korea in 2020.

Gyo-dong Island is situated in the Han River estuary neutral zone, which does not have a defined military demarcation line (MDL). During low tide, the water level drops significantly, making it possible to walk across. This characteristic has historically made it a popular defection route. The widest part of the estuary spans about 10 kilometers, while the narrowest section is around 900 meters.

In addition to Gyo-dong Island, the North-South Limit Line (NLL) sea area nearby is another common escape route for North Koreans heading south. The area’s complex coastline, the close proximity between North and South Korea, and relatively loose surveillance by North Korean forces contribute to its use as a defection route.

Strong Marine Corps Forces Guarding the Korean Peninsula’s Coast

The formidable Marine Corps safeguards Ganghwa Island’s coastline. The 2nd Marine Division patrols key areas, including Gimpo, Ganghwa Island, Gyo-dong Island, and Mado. It covers the entire Han River estuary and maintains vigilance along the border with North Korea.

Recent defection cases have sparked criticism of the military’s border operations. Defectors have been discovered only after crossing South Korean territory, swimming, or walking across the water. The question is whether the latest defection, which occurred after a seven-year hiatus, points to a lapse in border security.

The military asserts that it tracked the North Korean defectors from their moment of departure and guided them safely into South Korean territory. National Defense Minister Shin Won-sik addressed the issue at a National Assembly Defense Committee meeting: “We continuously monitored the defectors from their departure and successfully guided them into South Korean territory. While we may not be able to disclose all details, we will report on permissible aspects.”

The border operation was adequate if the Defense Minister’s account was accurate and the defector was observed and guided. The Marine Corps appears to have conducted a successful “watertight” operation with minimal resources.

Possibility of “Mass Defection Routes” Amid North Korean Unrest

The Marine Corps’ 2nd Division oversees a 255-kilometer (158-mile) border area on the western side of the capital region, including Gimpo and Ganghwa. This stretch surpasses the 250-kilometer (155-mile) Demilitarized Zone (DMZ), which approximately ten Army divisions protect. Notably, Gyo-dong Island, a frequent defection route, has a 37.5-kilometer (23.3-mile) coastline. While an Army division typically covers a similar length of the DMZ, only about 200 Marines patrol Gyo-dong Island.

Some analysts suggest the recent defection may have been influenced by North Korean loudspeaker broadcasts operated by the South Korean military. Depending on weather conditions, these high-powered loudspeakers can transmit messages up to 20 kilometers (12.4 miles).

Professor Park Won-gon from Ewha Womans University commented, “Walking across, as seen in this case, is a significant challenge for defectors. However, it likely caused considerable disruption within North Korea. If unrest continues, such methods could potentially become a ‘mass defection route.'”

Military sources emphasize the need for a thorough investigation to determine if the loudspeaker broadcasts had any impact. A Joint Chiefs of Staff official noted, “It takes more than three months to evaluate the effects of psychological operations using loudspeaker broadcasts.”