Was the American Civil War the “bloodiest civil war in history”?

The American civil war is maybe the bloodiest in the history of the United States but isn't the bloodiest in the Americas - the conquista (and the following Indian wars in North America and South America) and the Mexican revolution is the worst ones.

Absolutely the US Civil war is not close to being the bloodiest, there were none of the indiscrimate massacres of civilians that were a feature of most civil wars

In just war casualties in soldiers, the U.S. Civil War had more dead then all U.S wars combined. Accurate Civil wars totals are impossible to pin down - between 625,000-650,000 is a pretty good estimate. As far as deaths per square mile on one battlefield, the Roman battle at Cannae against Hannibal had over 100,000 deaths in one day, per square mile this is incredible for hand-to-hand combat. Must have been a sight of pure slaughter.

The bloodiest civil war in history was the An Lushan Rebellion from 755 to 763 A.D. in China. The war occurred because general An Lushan declared himself emperor and tried to overthrow the emperor of China.

Historians estimate that as many as 36 million people died in the war. A census in 755 recorded a population of 52,919,309 in 8,914,709 taxpaying households. A census taken in 764, a year after the rebellion, recorded only 16,900,000 in 2,900,000 households. The difference between these two is where historians get a death toll of 36 million. A lower estimate puts the death toll at 13 million. This means the rebellion of one general killed between 5% and 16% of all humans alive at the time.

The American Civil War was not the bloodiest in history since the An Lushan Rebellion death toll outpaced it by about 35.4 million deaths. It was the bloodiest war in American history, but that was not the question asked.

Rwanda: as many as 1 000 000 in just 100 days. That is surely a record.

I suspect the reason "bloodiest" is used to coin the American civil war has more to do with the changing technology and the impact it had on the conflicts rather than on actual casualty numbers. At the beginning of the war, most firearms were cap and ball muskets. Later, the minieball or conical bullet was adopted as well as rifled muzzle loaders and wounds drastically increased in number and severity. Later, as you mentioned, even cartridges and repeating arms were used. It is often called the first "modern" war because of the technology.

I believe the original poster may have mis-remembered the "TV documentary" statement. I've often heard/read it claimed that the American Civil War was the bloodiest war in U.S. history, but I've never seen it claimed that it was the bloodiest civil war (ever) in history. However, even the claim that it's the bloodiest war in U.S. history is debatable. The figures usually quoted for "American" Civil War casualties are a sum of U.S. and C.S. casualties. By that type of measure (U.S. + enemy casualties) quite a few wars in which the U.S. has since participated were bloodier. In terms of U.S. casualties alone, then WWII has been the United States' bloodiest conflict to date.

Yes the Civil War has thus far been the bloodiest war in American history in terms of American casualties. Approximately half of all war time casualties are from that era.

Q. How many soldiers died in the Civil War as compared to other American wars?

Roughly 1,264,000 American soldiers have died in the nation's wars--620,000 in the Civil War and 644,000 in all other conflicts. It was only as recently as the Vietnam War that the amount of American deaths in foreign wars eclipsed the number who died in the Civil War.

-civilwar.org

The Russian Civil War (1917-23) and the Chinese Civil War (1930s-1949) have it beaten handily.

It remains the bloodiest war in American History, partly because both sides were Americans.

The bloodiest civil war I can think of is the Taiping Rebellion in 19th century China. That conflict is generally thought to have a death toll of 20 million.

Note that this is an estimate made by western observers. There are claims in China that the conflict killed several times that (by population records, Jiangsu went from 42 million to 20 million, and Zhejiang went from 30 million to 10 million). Actual figures are difficult to determine - those extraordinarily high numbers seem quite dubious.

However, what is certain is that it was an extremely bloody conflict where both sides massacred civilians regularly. Chinese records of the time is replete with phrases like:

• 但有黃篙白骨，並無居民市鎮，竟日不見一人: "I see white bones scattered about and no residents or citizens; no one was seen the whole day."
• 不聞雞犬聲 違見餓民殭斃於道: "there is no sound of chicken or dogs, only the stiff bodies of people starved to death.
• 屠駐防嬰孺無遺，復驅隱匿之婦女出聚寶各門盡于橋上殺之，河水皆赤: "The whole garrison of youngsters were slaughtered without survivors; then they drove the women who had hidden onto a bridge for execution, and the river ran red."
• 數百萬生靈，城初破死者蓋已不下數十萬矣: "Of the several million souls who resided there, by the time the city had fallen several hundred thousand had already died."