In 1870, the U.S. census expanded the collection of employment statistics to include children.
It found that 75,000 children under age 15 worked — a number that didn't include those "employed" in family businesses or on family farms.
A popular attitude at the time was that children had always worked and, therefore, children working in modern industries was necessary and nothing unusual.
Since the beginning of time, they'd helped hunt and gather food, cook and clean, and otherwise provide for the family unit.
This belief didn't begin to substantially change until the early 20th century — a handful of years that would become known as the Progressive era.
Labor reformers began seriously campaigning against child labor in the 1890s, spreading photographs of children working in unsafe conditions in factories and mines.
Multiple attempts at anti-child labor legislation were introduced to Congress (though the pieces that passed were often declared unconstitutional) .
Progressive-era campaigning slowly changed Americans' views of child labor, and by the mid-1930s fewer children were working than ever before.
By 1938 child labor was for the most part illegal in the United States.
Today there are limited protections for some child workers: children are legally allowed to work on family farms for an unlimited number of hours, for example, as long as they attend school.
