One of the mandates in the Congressional Charter of the VFW is to “perpetuate the memory and history of our dead”. IAW such, I set out on a quest to document these POWs and their final resting places. In 1997, the Veterans of Foreign Wars District 5 in Thailand  had placed a memorial plaque adjacent to the Bridge over the River Kwai in Kanchanaburi. [see Section 14.1]
I had always heard that the numbers displayed on that memorial were in dispute. It reads that “approximately 700” US POWs worked the railway and 356 died in the process. It seems the second number is quite inaccurate! The best data I can find via multiple sources is that 684 US POWs were in Thailand or Burma of whom 131 (18%) died there. 65 of those were Army, 62 were Navy & 4 Marines; plus a number of them died post-TBR or soon after liberation from POW-related issues.
The US POWs were less than 1% of the military prisoners who worked the railway. Most were British (29,472; 48%), Australians (23,002; 21%); Dutch (17,985; 29%); for a grand total of over 61,000. But even this figure pales compared to the number of Asian Forced Laborers (aka romusha) who may have numbered over 500,000! [see Section 20.] The US POWs came mainly from two groups: survivors of the sinking of the USS Houston (CA-30) in the Strait of Sundra in MAR 1942 and members of the 131 Field Artillery (FA) Regiment (Texas National Guard; TXNG) who had been deployed to the island of Java in JAN 1942 to assist the Dutch Army. Most of the Dutch prisoners were Army (aka KNIL) captured at the same time when the island was overrun by the Japanese. The British and Australians came mainly from the fall of Singapore but others were also captured in the Dutch East indies (DEI). Only 336 members of the USS HOUSTON crew of 937 survived the sinking and were taken prisoner as they made their way ashore. Just about 300 of those Sailors (273) and Marines (27) were eventually sent to Burma and/or Thailand to build the railway. They joined the 374 Soldiers affiliated with the 131st FA Regiment.
In addition, there were 7 Merchant Mariners who survived the sinking of the SS Sawolka who were sent to the TBR. All of whom survived their captivity. Finally, there were 3 additional US POWs. Charles D Mott  was a civilian volunteer with the FLYING TIGERS Squadron who was taken as a POW and spent his TBR time at Nong PlaDuk. The final 2 were true civilians who due to various circumstances found themselves on Java in early 1942. Their stories are told in Section 3.2.
It makes for a total of 684 US POWs who were sent to Thailand-Burma of whom 549 (80%) survived the ordeal. Overall, from these units, 954 men were taken as POWs; 792 of whom survived (80%).
If we were to reprise that memorial plaque today, it would read “of the approximately seven hundred servicemen…” and “In special memory of the one hundred and thirty-three who perished…”
COL(ret) US ARMY Medical Corps
Life Member VFW Post 9951 Bangkok
DISCLAIMER: The Kansas HQ of the Veterans of Foreign Wars of the United States partially funded the development of this website.
 See Section 14.1 for information related to the 1997 memorial
 https://flyingtigersavg.com/mott-charles-d/ and Section 3.8b