There were almost 700 thousand slaves in the US in 1790, which equated to approximately 18 percent of the total population, or roughly one in every six people. By 1860, the final census taken before the American Civil War, there were four million slaves in the South, compared with less than 0.5 million free African Americans in all of the US. Of the 4.4 million African Americans in the US before the war, almost four million of these people were held as slaves; meaning that for all African Americans living in the US in 1860, there was an 89 percent* chance that they lived in slavery. A brief history Trans-Atlantic slavery began in the early sixteenth century, when the Portuguese and Spanish forcefully brought captured African slaves to the New World, in order to work for them. The British Empire introduced slavery to North America on a large scale, and the economy of the British colonies there depended on slave labor, particularly regarding cotton, sugar and tobacco output. In the seventeenth and eighteenth century the number of slaves being brought to the Americas increased exponentially, and at the time of American independence it was legal in all thirteen colonies. Although slavery became increasingly prohibited in the north, the number of slaves remained high during this time as they were simply relocated or sold from the north to the south. It is also important to remember that the children of slaves were also viewed as property, and (apart from some very rare cases) were born into a life of slavery. Abolition and the American Civil War In the years that followed independence, the Northern States began gradually prohibiting slavery, and it was officially abolished there by 1805, and the importation of slave labor was prohibited nationwide from 1808 (although both still existed in practice after this). Business owners in the Southern States however depended on slave labor in order to meet the demand of their rapidly expanding industries, and the issue of slavery continued to polarize American society in the decades to come. This culminated in the election of President Abraham Lincoln in 1860, who promised to prohibit slavery in the newly acquired territories to the west, leading to the American Civil War from 1861 to 1865. Although the Confederacy (south) were victorious in much of the early stages of the war, the strength in numbers of the northern states (including many free, black men), eventually resulted in a victory for the Union (north), and the nationwide abolishment of slavery with the Thirteenth Amendment in 1865. Legacy In total, an estimated twelve to thirteen million Africans were transported to the Americas as slaves, and this does not include the high number who did not survive the journey (which was as high as 23 percent in some years). In the 150 years since the abolishment of slavery in the US, the African-American community have continuously campaigned for equal rights and opportunities that were not afforded to them along with freedom. The most prominent themes have been the Civil Rights Movement, voter suppression, mass incarceration and the relationship between the police and the African-American community has taken the spotlight in recent years.

This statistic shows the number of black men and women in the US from 1820 until 1880. Slavery was legal in the Southern States of the US until 1865, when the Thirteenth Amendment was added to the US Constitution after the American Civil War. Until that time all of the slaves included in this statistic were registered as living in the South, whereas the majority of the free, black men and women lived in the Northern States. From the data we can see that, while the slave experience was very different for men and women, there was relatively little difference between their numbers in each respective category. While female slaves were more likely to serve in domestic roles, they were also more likely to be working in the lowest and unskilled jobs on plantations, whereas men were given more skilled and physically demanding roles. As slavery was abolished in 1870, all black people from this point were considered free in the census data. It is also worth noticing that in these years the difference in the number of men and women increased, most likely as a result of all the black male soldiers who fell fighting in the American Civil War.

Brazil conducted its first nationwide census in 1872, just 16 years before slavery's official abolition in 1888. Modern estimates place Brazil's total population in 1872 at approximately 10.3 million; the exclusion of non-white infants and indigenous populations from the census is likely the cause of this deficit. The 1872 census showed that non-whites made up the majority of Brazil's population at this time, at roughly 5.75 million, compared to the white population of 3.79 million. Of these 5.75 million, over 4.2 million were free, compared to 1.5 million living in slavery; this gives a ratio of almost three free non-whites for every one slave. To compare, in the United States in 1860, there were at least eight slaves for every one free person of color in the years leading up to slavery's nationwide abolition.

The issue of race and slavery was arguably the largest cause of the American Civil War, with the southern states seceding from the Union as the practice of slavery became increasingly threatened. From the graph we can see that roughly 16.5 percent of the entire US population at this time was black, and the vast majority of these were slaves. In 1860 there were almost 27 million white people, four and a half million black people, and less than one hundred thousand non-black or white people (mostly of Native/Latin American or East-Asian origin).

Throughout the final century of legal slavery in Jamaica, the population grew from below 87 thousand in 1734 to over 317 thousand in 1823. In the last decade, however, this number fell by 15 thousand, as many slave owners sold their slaves to other non-British colonies in anticipation of slavery's abolition. In Jamaica in August, 1834, all slaves were officially emancipated, although the majority then became "apprentices". The apprentice system saw little change for most ex-slaves, who were obligated to work 45 hours per week without pay, but with some minor improvements to their protections under law; this system was eventually scrapped in 1838.

Brazil conducted its first nationwide census in 1872; this census gave total populations of 4.2 million free non-whites, 1.5 million slave non-whites, and 3.8 million whites. Indigenous people and those of mixed indigenous descent were largely excluded from the census, although an overall figure of 0.4 million was given for the entire country. These figures combined to give a total of 9.9 million (modern UN estimates put the total at 10.3 million in 1872; likely due to the census' exclusion of many non-white infants).

The state of Minas Gerais had the largest population, at over two million people, with the neighboring states of Bahia and Rio de Janeiro with the second and third largest populations respectively. East Brazil was the region with the largest population, followed by the northeast and then south. In terms of ethnicity, non-whites outnumbered white people in every region except for the south, and free people of color outnumbered slaves in every state except for Rio de Janeiro.

Between 1775 and 1841, the population of Cuba grew to almost six times its size, from approximately 170 thousand people to over one million. During these years, Cuba was a Spanish colony, where slavery remained legal. In 1841, slaves counted for almost 45% of the total population.

Sugar industry A large reason for this growth was the emergence of the sugar industry, as production was relocated from areas of the Caribbean where slavery was abolished (most notably Haiti in 1804 and Jamaica in 1834). Although Cuba had been a Spanish colony for almost three centuries before these figures begin, it was economically isolated and trade with other nations was restricted; following a brief occupation by the British in the 1860s, international trade became encouraged, and a slave-based plantation complex emerged. By the middle of the 19th century, Cuba had established itself as the largest producer of sugar in the world (a position that it held until the mid-20th century), with the U.S. as it's primary consumer.

Gender differences From the figures for 1827 and 1841, the disparities between the male and female populations become apparent. Males migrated to the Americas at a much higher rate than females, while African males were also captured and enslaved at a higher rate than females during the Atlantic slave trade. This is reflected in the slave and white populations, although the difference within the slave population is much greater. Conversely, among free people of color, the female population population is actually higher than the number of males; this was due to a number of reasons, such as higher rates of manumission among females (the ratio of female to male manumissions was estimated to be around 3:2 in the Caribbean in the 19th century) and higher life expectancy.

According to the Brazilian census of 1872, approximately 26 percent of Brazil's non-white population was living in slavery, while 74 percent of the non-white population were legally free. Rio de Janeiro was the only region where there were more non-white people living in slavery than living in freedom.

Generally speaking, the northern and northeastern regions of Brazil had a smaller share of their non-white populations living in slavery than the southern and eastern regions at this time; this was likely due to the concentration of slave trading activities further from the equator in the second half of the 19th century. The reason for this was the British Navy's anti-slave-trade patrols in the Atlantic between 1808 and 1867, following the British abolition of the slave trade in 1807; this saw Portuguese and Brazilian slave traders take southern routes to the Americas to avoid interception, ultimately resulting in increased traffic to Brazil's southeasterly ports.

This statistic shows the population of the United States in the final census year before the American Civil War, shown by race and gender. From the data we can see that there were almost 27 million white people, 4.5 million black people, and eighty thousand classed as 'other'. The proportions of men to women were different for each category, with roughly 700 thousand more white men than women, over 100 thousand more black women than men, and almost three times as many men than women in the 'other' category. The reason for the higher male numbers in the white and other categories is because men migrated to the US at a higher rate than women, while there is no concrete explanation for the statistic regarding black people.

In 1789, on the eve of the Haitian (and French) Revolution, the French colony of St Domingue had an estimated population of 556 thousand people. Of these, 500 thousand are thought to have been African slaves (approximately half of the entire Caribbean's slave population at the time), while just over ten percent of the population were whites or free people of color. Following the Haitian Revolution's conclusion in 1804, Haiti would become just the second nation in the Americas to gain its independence, and was the first (and only) country in the world to have been established by former slaves.

Between 1501 and 1866, it is estimated that over 12.5 million people were forced onto ships in Africa, and transported to the Americas as slaves. Furthermore, it is estimated that only 10.7 million of these slaves disembarked on the other side of the Atlantic, meaning that roughly 1.8 million did not survive the journey. The transatlantic slave trade was a part of the triangular trade route between Europe, Africa and the Americas, during the sixteenth and nineteenth centuries. Generally speaking, this route saw European merchants bring manufactured products to Africa to trade for slaves, then transport the slaves to the Americas to harvest raw materials, before taking these materials back to Europe where they would then be consumed or used in manufacturing. Slavery was an integral part in funding the expansion of Europe's colonial empires, which shaped the modern and highly globalized world in which we live today.

The Middle Passage As with trade, the slave journey was also broken into three parts; the First Passage was the stage where slaves were captured and transported to African ports, the Middle Passage was the journey across the Atlantic, while the Final Passage was where the slaves were transported to their place of work. The death toll in the First Passage is thought to be the highest of the three stages, as millions were killed or fatally wounded as they were captured, however a lack of written data and historical evidence has made this number difficult to estimate. In contrast, shipping records from the time give a much more accurate picture of the Middle Passage's death toll, and this data suggest that roughly 14.5 percent of slaves did not survive the journey. The reason for this was the harsh and cramped conditions on board; slave ships were designed in such a way that they could fit the maximum number of slaves on board in order to maximize profits. These conditions then facilitated the spread of diseases, such as smallpox and dysentery, while malnutrition and thirst created further problems. Generally, slavers aimed to keep slaves as healthy (therefore; profitable) as possible, although there are countless examples of mistreatment and punishment of slaves by their captors, and several cases where slaves were exterminated by the crew as provisions ran low.

Rise and fall of the transatlantic slave trade

The European arrival in the Americas also saw the introduction of virgin soil epidemics (new diseases being introduced to biologically defenseless populations) which decimated the indigenous populations. The abundance of natural resources, but lack of available labor led to the rise of the transatlantic slave trade. Until the mid-1600s, Portuguese traders had a near-monopoly on this trade, supplying slaves to the newly expanding Spanish and Portuguese empires in South America. As other European powers began to expand their empires in the Caribbean and North America, the slave trade grew dramatically, and during the eighteenth century, the number of slaves being brought to the New World increased from an annual average of thirty thousand in the 1690s to 87 thousand in the 1790s. The transatlantic slave trade reached its peak between the 1750 and 1850, and an average of 74 thousand slaves were brought to the Americas each year between these dates. The largest decline came as the slave trade was disrupted during the American War of Independence (1775-1783), although the trade became weakened as the abolitionist movement gained momentum in Europe and the Americas around the turn of the century. The most significant impacts came as the slave trade was abolished in Britain and the U.S. in 1807 and Brazil in 1831, and Britain then used its position as the global superpower to impose abolition on other nations and used the Royal Navy to enforce these measures. While most nations abolished the slave trade in the early 1800s, it would take decades before the actual practice of slavery would be abolished; today, slavery is illegal in almost every country, however modern slavery in the forms of forced labor, human trafficking and sexual exploitation continues to be prevalent across the globe.

At the beginning of the 19th century, the U.S. labor force was approximately 1.9 million people, with slaves making up over half a million (28 percent) of this number. The share of slaves then increased to almost one third of the overall workforce in the next decade, but dropped to roughly one fifth by 1860; the year before the American Civil War. While the total number of slaves grew by several hundred thousand in each decade, their share of the U.S. labor force decreased due to the high levels of European migration to the U.S. throughout the 19th century. This wave of mass migration was an influential factor in slavery's eventual abolition, as Europeans met the labor demands that had previously been fulfilled by slaves, and those fleeing persecution and oppression in Europe were often sympathetic to the plight of slaves. Nonetheless, the majority of European migrants arrived in the industrialized, northern states, most of which had already abolished slavery in the 18th century, and slave labor was concentrated in the agricultural south at this time; this divide would prove fundamental in the outbreak of the American Civil War.

Between 1628 and 1860, it is estimated that almost 390 thousand Africans were transported as slaves to European colonies in Mainland North America. This figure refers only to those who survived the journey, as it is also thought that over 470 thousand captives embarked on these ships at African ports, however 84 thousand died en route (giving a mortality rate of 17.7 percent). The transportation of African slaves to the Thirteen Colonies was highest in the mid-18th century (although there was some fluctuation), before an observable decline around the time of the American Revolutionary War. Following independence, the importation of slaves remained lower than in previous decades, until it saw a sharp increase in the five years leading up to the slave trade's abolition. In 1807 alone, the year before the U.S. abolished the slave trade, almost 29 thousand slaves were imported from Africa into the U.S. Following this, activity declined greatly; the relatively small number of slaves imported from Africa to the U.S. were most likely into the Spanish territory of Florida. Smuggling also existed on a smaller scale; this accounts for the entries in 1858 and 1860.

Throughout the history of the transatlantic slave trade, approximately 5.7 million of the 12.5 million African slaves who embarked on slave ships did so in ports along the region of West Central Africa and St. Helena. Today, these regions are in the countries of Angola, Democratic Republic of the Congo, Gabon, and the Republic of the Congo. The majority of the rest were taken from West Africa, embarking in ports between the present-day countries of Senegal and Gabon, while a smaller number of slaves were captured in the southeast of Africa. Senegambia and off-shore Atlantic islands had the highest number of captives taken from that region in the 16th century, however West Central Africa and St. Helena was the region where most slaves embarked on their journey across the Atlantic in the following centuries. As Portuguese traders were responsible for transporting the largest volume of slaves to the Americas, it is unsurprising that many of the busiest ports in the transatlantic slave trade were in Portuguese-controlled enclaves along the African coast.

In the past four centuries, the population of the United States has grown from a recorded 350 people around the Jamestown colony of Virginia in 1610, to an estimated 331 million people in 2020. The pre-colonization populations of the indigenous peoples of the Americas have proven difficult for historians to estimate, as their numbers decreased rapidly following the introduction of European diseases (namely smallpox, plague and influenza). Native Americans were also omitted from most censuses conducted before the twentieth century, therefore the actual population of what we now know as the United States would have been much higher than the official census data from before 1800, but it is unclear by how much. Population growth in the colonies throughout the eighteenth century has primarily been attributed to migration from the British Isles and the Transatlantic slave trade; however it is also difficult to assert the ethnic-makeup of the population in these years as accurate migration records were not kept until after the 1820s, at which point the importation of slaves had also been illegalized. Nineteenth century In the year 1800, it is estimated that the population across the present-day United States was around six million people, with the population in the 16 admitted states numbering at 5.3 million. Migration to the United States began to happen on a large scale in the mid-nineteenth century, with the first major waves coming from Ireland, Britain and Germany. In some aspects, this wave of mass migration balanced out the demographic impacts of the American Civil War, which was the deadliest war in U.S. history with approximately 620 thousand fatalities between 1861 and 1865. The civil war also resulted in the emancipation of around four million slaves across the south; many of whose ancestors would take part in the Great Northern Migration in the early 1900s, which saw around six million black Americans migrate away from the south in one of the largest demographic shifts in U.S. history. By the end of the nineteenth century, improvements in transport technology and increasing economic opportunities saw migration to the United States increase further, particularly from southern and Eastern Europe, and in the first decade of the 1900s the number of migrants to the U.S. exceeded one million people in some years. Twentieth and twenty-first century The U.S. population has grown steadily throughout the past 120 years, reaching one hundred million in the 1910s, two hundred million in the 1960s, and three hundred million in 2007. In the past century, the U.S. established itself as a global superpower, with the world's largest economy (by nominal GDP) and most powerful military. Involvement in foreign wars has resulted in over 620,000 further U.S. fatalities since the Civil War, and migration fell drastically during the World Wars and Great Depression; however the population continuously grew in these years as the total fertility rate remained above two births per woman, and life expectancy increased (except during the Spanish Flu pandemic of 1918).

Since the Second World War, Latin America has replaced Europe as the most common point of origin for migrants, with Hispanic populations growing rapidly across the south and border states. Because of this, the proportion of non-Hispanic whites, which has been the most dominant ethnicity in the U.S. since records began, has dropped more rapidly in recent decades. Ethnic minorities also have a much higher birth rate than non-Hispanic whites, further contributing to this decline, and the share of non-Hispanic whites is expected to fall below fifty percent of the U.S. population by the mid-2000s. In 2020, the United States has the third-largest population in the world (after China and India), and the population is expected to reach four hundred million in the 2050s.

From the sixteenth to the mid-nineteenth centuries, Portuguese and Brazilian traders were responsible for transporting the highest volume of slaves during the transatlantic slave trade. It is estimated that, of the 12.5 million African slaves captured during this time, more than 5.8 million were transported in ships that sailed under the Portuguese and, later, Brazilian flags. British traders transported the second-highest volume of slaves across the Atlantic, totaling at almost 3.3 million; over 2.5 million of these were transported in the 18th century, which was the highest volume of slaves transported by one nation in one century.

According to records regarding the White House (i.e. census data and purchase or rental contracts), at least 201 slaves were known to have been hired from their owner to help build the White House and Capitol Building between 1792 and 1800. The source details that many slaves involved in this feat were undocumented, therefore the number of slaves who actually took part was likely much higher. Similarly, records also show that there were a number of slaves recorded as living or working on the White House grounds until 1850, during the tenure of ten of the first twelve U.S. presidents. It is important to note, however, that these figures apply only to the slaves who moved with the president to the White House (or were hired from their respective owner), and this data is not reflective of the number of slaves owned by U.S. presidents throughout their lifetimes.

Of these first twelve presidents, John Adams and William Henry Harrison were the only to not have slaves living with them in the White House, although Harrison was an advocate of slavery and was a slave owner during his lifetime. Adams' son, John Quincy Adams, also held a strong anti-slavery stance throughout his political career, however, when John Quincy's sister-in-law and brother-in-law died in 1813 and 1815 respectively, their four children went to stay in the White House and brought with them a small number of slaves.

Portuguese and Brazilian traders were responsible for transporting the highest volume of slaves during the transatlantic slave trade. Portugal held a near-monopoly on the transatlantic slave trade in the 16th century, due to their network of factories along the African coast, and also imported hundreds of thousands of slaves into Brazil and the Caribbean in the 19th century.

Emergence of other powers The rise of the British, French and Dutch empires in the 17th century was also fueled by profits made from slave labor, and, to a lesser extent, the slave trade. Throughout the 1700s especially, British ships transported more slaves across the Atlantic, as the empire expanded across the Caribbean and North America. Similarly to Britain, ships flying under the flag of the Thirteen Colonies or the U.S. saw relatively large growth from the mid-1700s onwards (apart from a brief disruption caused by the American Revolutionary War), with the number of slave imports peaking in the early years of the 1800s. However, both Britain and the U.S. abolished the slave trade in 1807 and 1808 respectively, which ended their official participation in the widespread importation of slaves. French imports of slaves peaked in the late 1780s, however the numbers then plummeted from 1790 onwards, due to the instability and turmoil caused by the French Revolution and Haitian Revolution.

The largest empire was one of the smallest slave importers While a significant number of slaves eventually ended up in the Spanish Americas, Spanish merchants did not explicitly transport slaves in the same quantities as other powers' merchants. The was rooted in the Spanish legacy of importing slaves through foreign powers (namely Portugal, largely due to the Treaty of Tordesillas), and the forced labor of indigenous societies. However this changed drastically in the 19th century, as independence movements swept across Spain's mainland colonies in the Americas, and Spain then invested heavily into its Caribbean colonies (particularly Cuba).

In Africa, where domestic slavery was the predominant form of slavery, female slaves were usually favored as they were perceived as being more easily-controlled and less likely to rebel. In the Americas, however, where productive slavery was more prevalent, male slaves were preferred due to the physical intensity of the labor and the perception that they were more likely to survive seasoning or acclimatization to the new environment (in reality, male slaves in the New World had a much higher mortality rate than female slaves).

It is often quoted that slavers aimed to capture two male slaves for every female slave, yet most sources suggest that this target was rarely met. The averages shown here suggest that the gender ratio among slaves was around 179 males for every 100 females, although the difference varied by region, national carrier and century; for example, a much higher share of male slaves was transported to Cuba in the 19th century, than those transported to British Caribbean colonies in the 18th century. Because of these variations, and the lack of gender ratio from several of the earliest and busiest routes (namely Portuguese voyages to Brazil, which was the most common destination for slaves during the transatlantic slave trade), historians are often reluctant to make overall estimates for the gender ratio during the transatlantic slave trade. Nonetheless, a ratio of 170 to 180 males per 100 females is the most common consensus given among modern historians.

From 1501 until 1866, it is estimated that the transatlantic slave trade saw more than 12.5 million African people forcefully put on slave ships and transported to the Americas. Of these 12.5 million, only 10.7 million disembarked on the other side of the Atlantic, meaning that approximately 1.8 million (14.5 percent) did not survive the journey, known as the Middle Passage. Throughout most of the the sixteenth century, the mortality rate was around thirty percent, it then fell below twenty percent in the late seventeenth century, and below fifteen percent in the late eighteenth century. There was a slight increase in the mid-1800s, before the transatlantic slave trade effectively ended in the 1860s. The overall average mortality rate is lower than the rate in most decades, due to the larger numbers of captives transported in the late 1700s; a significant number of these voyages were between Africa and Brazil, which was generally the shortest of the major routes.