MIA Facts Site

Thach Ba and the

"Island Fortress"

NW of Hanoi lies the Thach Ba reservoir, also referred to as Thach Ba Lake or Ho Thach Ba.  The lake, or, reservoir, is formed by damming the Red River.  The lake provides water to Hanoi and to farmland all over NW Vietnam.  The level of water in the lake varies from very high to quite low.  The lake is filled with tiny islands, which are the tops of the hills in areas that were flooded when the lake was formed.  As the water level goes up and down, more or fewer islands appear.  At high water, there are few islands; at low or medium water, islands pop up all over the place.

Garwood's Claims

On the surface, Garwood's "island fortress" sighting is a simple story.  He claims that he was sent  to an island in the midst of Thach Ba lake to repair a generator.  He drove to a spot on the side of the lake where he got onto a small boat and motored out into the middle of the lake where he got out of the boat.  He claims to have walked up toward the center of the island where he found the generator shed next to a large masonry building that resembled a "fortress."  Garwood says that, while working on the generator,  he saw a number of US POWs in the "island fortress."

There are, however, wide inconsistencies in Garwood's "island fortress" story.

Where was the fortress on the island?

He has located the fortress as being close to the shore, or a five-minute walk from the shore, or a fifteen-minute walk from the shore.

When did this incident occur?

September 1977, October 1977, mid-December 1977, or March 1978.  The time varies each time he tells the story.

How many Americans did he see?

Twenty, thirty, thirty to forty, a group that he could not count.

Describe the "fortress."

He describes first a large concrete building, then a large brick building, then a group of masonry buildings; he describes the place as having a wall surrounding it then as not having a wall surrounding it..

Where was the generator he worked on?

Detached from the "fortress" but close to it; or, inside the walls of the "fortress;" or, in a small building attached to the walls of the "fortress."

There is one element of this story that is consistent:  Garwood insists that he got into a boat and motored well into the center of the lake to the island where he made his sighting.


Thach Ba Lake is well-known to US intelligence.  It was monitored using satellite and other overhead photography for years.  Why?  Because we wanted to keep track of the water level so we would be able to determine if North Vietnam would have sufficient water for agricultural irrigation.  Thus, we have imagery of the lake -- of every square inch of it -- at various times of the year.

When Garwood's claims about the "island fortress" first surfaced in the WSJ, we had the imagery analysts pull all the shots we had of the lake and examine the imagery to find the fortress.  There is not, at any time of the year, at any water level, a building of any size on any island in the lake.  There is one small building, about six or eight feet square, on one island; it is a hydrolgoic monitoring station that keeps track of the lake levels and water quality.

During the September 1987 interviews, Garwood was shown a large mosaic photograph of Thach Ba Lake, assembled from satellite imagery.  He was asked to trace his route from his home in yen Bai to the lake.  He was dumbfounded.  Garwood simply stared at the photograph, looked at it from every angle, and asked how we were able to obtain such a photo.  It was clear that he had no idea about the extent of Thac Ba.  He was completely unable to trace his route; he could not even figure out where Yen Bai was in relation to the lake, even after we oriented him.


Garwood's claims to have visited an island in the center of Thach Ba Lake and to have seen a number of US POWs there are bogus.  Completely bogus.


In July 1993, a most bizarre incident played out.  Former Congressman Bily Hendon went to Vietnam where he traveled to the southern shores of Thach Ba.  There, he hired a boat and motored along the shore until he found a group of masonry buildings; some brick buildings where people were living.  Billy explored these buildings then left.

A few days later, Garwood, Senator Bob Smith, and a camera crew from ABC 20/20 arrived in Vietnam.  They traced the same route followed earlier by Hendon, boarded a rented boat, and motored along to the same buildings.  Garwood got out of the boat, walked up to the buildings, and announced that this was, indeed, his island fortress.  Bob Smith could hardly contain his enthusiasm.  Here, he claimed, was proof that DIA was lying when they said that no such "island fortress" existed.  The whole affair was bogus.  For the details, go to my MIA Fact Pages report on the "Island Fortress" caper of July 1993.