For more than 160 years, British courts sent convicted men, women and children across the Atlantic. Transportation began on a limited and uneven basis in the early seventeenth century, then became a formal part of the criminal justice system under the Transportation Act of 1718.

More than 50,000 people were transported from Britain and Ireland to mainland North America during the eighteenth century, in addition to smaller earlier groups. Most were sent to Maryland and Virginia, where their labour was sold for the term of their sentence. Many later entered the free population, leaving descendants who knew little or nothing of the circumstances in which they had arrived.

Early transportation depended heavily on private arrangements. Courts, merchants and shipowners used the colonies as destinations for people whom the authorities wished to remove, but the process was inconsistent and sometimes difficult to enforce.

The 1718 Act made transportation a regular sentence. Many offences that could previously have led to execution were punished by seven years overseas, while some people reprieved from death received terms of fourteen years or life. The expanding penal code later known as the Bloody Code exposed people to capital punishment for an increasing range of property offences, although relatively few death sentences were carried out.

Contractors received payment to carry prisoners across the Atlantic and recovered further costs by selling the right to their labour. Transportation consequently served British penal policy and colonial employers at the same time. It removed offenders from Britain, reduced pressure on prisons and supplied workers to colonial agriculture and industry.

Most transportees were men, but thousands of women were also sent. The surviving records include adults, adolescents and some younger children. They came from England, Wales, Scotland and Ireland, although the laws, courts and surviving documentation were not identical in every jurisdiction.

Property offences account for much of the recorded crime. People were transported for shoplifting, pickpocketing, housebreaking, receiving stolen goods, livestock theft, counterfeiting and other forms of larceny. Some had committed serious or repeated offences; others stole goods of modest value in lives shaped by insecure work, poor relief and recurring poverty. Political and military prisoners formed smaller, distinct groups.

A conviction tells us what a court found, but not the whole life of the person before it. Depositions, petitions and newspaper reports may reveal family responsibilities, employment, previous convictions or claims of innocence that are absent from a brief transportation entry.

Historical records often reduce people to labels such as thief, vagrant, disorderly woman, common prostitute or whore. Those descriptions should not automatically be read as formal offences or complete accounts of a person's circumstances. They could carry assumptions about poverty, sexuality and female behaviour as well as describe suspected conduct.

Women transported to America were commonly convicted of theft, receiving stolen goods and related property offences. Some also survived through sex work or kept disorderly houses, but a moralising description written by an official is not proof of how a woman supported herself. The original charge, indictment and verdict matter more than a later label.

The Atlantic crossing could take weeks in crowded and unhealthy conditions. On arrival, merchants advertised groups of convicts and sold purchasers the right to their labour for the remainder of a seven- or fourteen-year sentence. Around four fifths of those transported in the eighteenth century went to Maryland and Virginia, where tobacco cultivation created a sustained demand for workers.

Transported people became convict servants on farms, plantations and estates, in ironworks and workshops, and in domestic service. Their position differed in law from both voluntary indentured servants and enslaved Africans, whose bondage was hereditary and usually lifelong. Convict labour was nevertheless coerced. Workers could be bought, resold, punished and pursued if they ran away.

Outcomes varied. Some transportees died during the voyage or their term of service. Some escaped, committed further offences or attempted to return to Britain before their sentence had expired. Others completed their terms, married, practised a trade, acquired land or moved into another colony.

Freedom could obscure the past surprisingly quickly. A former convict might appear in later records only as a farmer, labourer, craftsperson, spouse or parent. Families had strong reasons to omit a degrading conviction, while descendants born in America may never have known about it. Names were also misspelled, shortened or deliberately changed, making the connection harder to recognise.

The outbreak of the American Revolution in 1775 closed colonial ports to convict ships, and the last arrivals reached the Chesapeake in 1776. Britain then held prisoners in gaols and prison hulks while seeking other destinations. Large-scale transportation to Australia began in 1787 with the departure of the First Fleet.

This divide can mislead family historians. An ancestor sentenced before the Revolution may have been sent to America, while a similar sentence from the late 1780s onward is more likely to lead towards Australia. A sentence of transportation did not always mean that the person actually left Britain, so the final destination must be established from further evidence.

Court proceedings, assize and quarter-session records, petitions, reprieves, gaol material, transportation contracts and shipping records can identify the person sentenced in Britain or Ireland. Colonial newspapers, runaway advertisements, servant sales, church registers, land records, probate files and court papers may show what happened after arrival.

The evidence is often divided between several archives and may describe the same person differently. A shared name or family story is not enough on its own; the dates, sentence, ship, purchaser, residence and later family must form a consistent chain.

If an ancestor appears suddenly in colonial Maryland, Virginia or a neighbouring colony without a clear place of origin, transportation may be one explanation.