On April 4, 1945, the U.S. 89th Infantry Division overran Ohrdruf, a subcamp of Buchenwald.

Buchenwald was partially evacuated by the Germans from April 6, 1945, until April 11, 1945.
In the days before the arrival of the American army, thousands of the prisoners were forced to join the evacuation marches.

Thanks in large part to the efforts of Polish engineer (and short-wave radio-amateur, his pre-war callsign was SP2BD) Gwidon Damazyn, an inmate since March 1941, a secret short-wave transmitter and small generator were built and hidden in the prisoners' movie room.
On April 8 at noon, Damazyn and Russian prisoner Konstantin Ivanovich Leonov sent the Morse code message prepared by leaders of the prisoners' underground resistance (supposedly Walter Bartel and Harry Kuhn):
To the Allies.
To the army of General Patton.
This is the Buchenwald concentration camp.
SOS.
We request help.
They want to evacuate us.
The SS wants to destroy us.

The text was repeated several times in English, German, and Russian.
Damazyn sent the English and German transmissions, while Leonov sent the Russian version.
Three minutes after the last transmission sent by Damazyn, the headquarters of the U.S. Third Army responded:
KZ Bu.
Hold out.
Rushing to your aid.
Staff of Third Army.

According to Teofil Witek, a fellow Polish prisoner who witnessed the transmissions, Damazyn fainted after receiving the message.

After this news had been received, inmates stormed the watchtowers and killed the remaining guards, using arms they had been collecting since 1942 (one machine gun and 91 rifles; see Buchenwald Resistance).

As American forces closed in, Gestapo headquarters at Weimar telephoned the camp administration to announce that it was sending explosives to blow up any evidence of the camp, including its inmates.
The Gestapo did not know that the administrators had already fled.
A prisoner answered the phone and informed headquarters that explosives would not be needed, as the camp had already been blown up, which was not true.

A detachment of troops of the U.S. 9th Armored Infantry Battalion, from the 6th Armored Division, part of the U.S. Third Army, and under the command of Captain Frederic Keffer, arrived at Buchenwald on April 11, 1945 at 3:15 p.m. (now the permanent time of the clock at the entrance gate).
The soldiers were given a hero's welcome, with the emaciated survivors finding the strength to toss some liberators into the air in celebration.

Later in the day, elements of the U.S. 83rd Infantry Division overran Langenstein, one of a number of smaller camps comprising the Buchenwald complex.
There, the division liberated over 21,000 prisoners, ordered the mayor of Langenstein to send food and water to the camp, and hurried medical supplies forward from the 20th Field Hospital.


Third Army Headquarters sent elements of the 80th Infantry Division to take control of the camp on the morning of Thursday, April 12, 1945.
Several journalists arrived on the same day, perhaps with the 80th, including Edward R. Murrow, whose radio report of his arrival and reception was broadcast on CBS and became one of his most famous:
I asked to see one of the barracks.
It happened to be occupied by Czechoslovaks.
When I entered, men crowded around, tried to lift me to their shoulders.
They were too weak.
Many of them could not get out of bed.
I was told that this building had once stabled 80 horses.
There were 1,200 men in it, five to a bunk.
The stink was beyond all description.

They called the doctor.
We inspected his records.
There were only names in the little black book, nothing more.
Nothing about who these men were, what they had done, or hoped.
Behind the names of those who had died, there was a cross.
I counted them.
They totaled 242.
242 out of 1,200, in one month.


As we walked out into the courtyard, a man fell dead.
Two others, they must have been over 60, were crawling toward the latrine.
I saw it, but will not describe it.

— Extract from Edward R. Murrow's Buchenwald Report – 15 April 1945.
On April 4, 1945, the U.S. 89th Infantry Division overran Ohrdruf, a subcamp of Buchenwald.
Buchenwald was partially evacuated by the Germans from April 6, 1945, until April 11, 1945. In the days before the arrival of the American army, thousands of the prisoners were forced to join the evacuation marches.
Thanks in large part to the efforts of Polish engineer (and short-wave radio-amateur, his pre-war callsign was SP2BD) Gwidon Damazyn, an inmate since March 1941, a secret short-wave transmitter and small generator were built and hidden in the prisoners' movie room. On April 8 at noon, Damazyn and Russian prisoner Konstantin Ivanovich Leonov sent the Morse code message prepared by leaders of the prisoners' underground resistance (supposedly Walter Bartel and Harry Kuhn):
To the Allies. To the army of General Patton. This is the Buchenwald concentration camp. SOS. We request help. They want to evacuate us. The SS wants to destroy us.
The text was repeated several times in English, German, and Russian. Damazyn sent the English and German transmissions, while Leonov sent the Russian version. Three minutes after the last transmission sent by Damazyn, the headquarters of the U.S. Third Army responded:
KZ Bu. Hold out. Rushing to your aid. Staff of Third Army.
According to Teofil Witek, a fellow Polish prisoner who witnessed the transmissions, Damazyn fainted after receiving the message.
After this news had been received, inmates stormed the watchtowers and killed the remaining guards, using arms they had been collecting since 1942 (one machine gun and 91 rifles; see Buchenwald Resistance).
As American forces closed in, Gestapo headquarters at Weimar telephoned the camp administration to announce that it was sending explosives to blow up any evidence of the camp, including its inmates. The Gestapo did not know that the administrators had already fled. A prisoner answered the phone and informed headquarters that explosives would not be needed, as the camp had already been blown up, which was not true.
A detachment of troops of the U.S. 9th Armored Infantry Battalion, from the 6th Armored Division, part of the U.S. Third Army, and under the command of Captain Frederic Keffer, arrived at Buchenwald on April 11, 1945 at 3:15 p.m. (now the permanent time of the clock at the entrance gate). The soldiers were given a hero's welcome, with the emaciated survivors finding the strength to toss some liberators into the air in celebration.
Later in the day, elements of the U.S. 83rd Infantry Division overran Langenstein, one of a number of smaller camps comprising the Buchenwald complex. There, the division liberated over 21,000 prisoners, ordered the mayor of Langenstein to send food and water to the camp, and hurried medical supplies forward from the 20th Field Hospital.

Third Army Headquarters sent elements of the 80th Infantry Division to take control of the camp on the morning of Thursday, April 12, 1945. Several journalists arrived on the same day, perhaps with the 80th, including Edward R. Murrow, whose radio report of his arrival and reception was broadcast on CBS and became one of his most famous:
I asked to see one of the barracks. It happened to be occupied by Czechoslovaks. When I entered, men crowded around, tried to lift me to their shoulders. They were too weak. Many of them could not get out of bed. I was told that this building had once stabled 80 horses. There were 1,200 men in it, five to a bunk. The stink was beyond all description.
They called the doctor. We inspected his records. There were only names in the little black book, nothing more. Nothing about who these men were, what they had done, or hoped. Behind the names of those who had died, there was a cross. I counted them. They totaled 242. 242 out of 1,200, in one month.

As we walked out into the courtyard, a man fell dead. Two others, they must have been over 60, were crawling toward the latrine. I saw it, but will not describe it.
— Extract from Edward R. Murrow's Buchenwald Report – 15 April 1945.
Buchenwald concentration camp