The province is known as an area of heavy fighting during the Vietnam War , as it was the second-most northerly province of the South Vietnam , close to the North Vietnamese border ( DMZ ) at the 17th parallel . More U.S. soldiers died in this province than in any other province in Vietnam ( 2,893 ) . The Massacre at Huế occurred here ; an estimated 2,800 to 6,000 civilians and Army of the Republic of Vietnam ( ARVN ) prisoners of war ( POWs ) were slaughtered by the Việt Cộng . Thừa Thiên-Huế province saw a large influx of North Vietnamese settlers soon after the Vietnam War ended , as with the rest of the former South . This province and neighbouring Quảng Nam Province suffered greatly from flooding in November 1999 . Thừa Thiên-Huế Province borders Quảng Trị Province to the north , the city of Đà Nẵng to the east , Quảng Nam Province to the south , and the Savannakhet , Salavan and Sekong provinces of Laos to the west . The Perfume River ( called Sông Hương or Hương Giang in Vietnamese ) passes through the province . The province also accommodates the Tam Giang Cầu Hai Lagoon , the largest lagoon in Southeast Asia , which is long with a surface area of . The province comprises four different zones : a mountainous area , hills , plains and lagoons separated from the sea by sandbanks . It has of beaches . The mountains , covering more than half the total surface of the province , are along the west and southwest border of the province , their height varying from to . The hills are lower , between and , with some points at , and occupy about a third of the province 's area , between the mountains and the plains . The plains account for about a tenth of the surface area , with a height of only up to above sea level . Between the hills are the lagoons which occupy the remaining five per cent of the province 's surface area
Massacre at Huế
Massacre at Huế
Thừa Thiên-Huế Province