In 1834 women working in the textile mills of Lowell, Massachusetts founded the Lowell Factory Girls Association. In September 2020 I found this union
documented on the AFL-CIO.org website of America's largest union organization. Because in my experience over the past fifteen years of writing this database I have found that institutional articles on historical topics are often removed from institutional websites I decided to quote most of the AFL-CIO text on this topic:
"The Lowell, Mass., textile mills where they [Lowell mill women] worked were widely admired. But for the young women from around New England who made the mills run, they were a living hell. A mill worker named Amelia—we don't know her full name—wrote that mill girls worked an average of nearly 13 hours a day. It was worse than "the poor peasant of Ireland or the Russian serf who labors from sun to sun." Lucy Larcom started as a doffer of bobbins when she was only 12 and "hated the confinement, noise, and lint-filled air, and regretted the time lost to education," according to one historian.
"In 1834, when their bosses decided to cut their wages, the mill girls had enough: They organized and fought back. The mill girls "turned out"—in other words, went on strike—to protest. They marched to several mills to encourage others to join them, gathered at an outdoor rally and signed a petition saying, "We will not go back into the mills to work unless our wages are continued."
"No one had ever seen anything like this. But if the mill girls were exuberant, managers and owners were horrified. "An amizonian [sic] display," one fumed. "A spirit of evil omen has prevailed." And they determined to crack down on the mill girls.
"A showdown came and the bosses won. Management had enough power and resources to crush the strike. Within a week, the mills were operating nearly at full capacity. A second strike in 1836—also sparked by wage cuts—was better organized and made a bigger dent in the mills' operation. But in the end, the results were the same.
"Those were hard defeats, but the mill girls refused to give up. In the 1840s, they shifted to a different strategy: political action. They organized the Lowell Female Labor Reform Association to press for reducing the workday to 10 hours. Women couldn't vote in Massachusetts or anywhere else in the country, but that didn't stop the mill girls. They organized huge petition campaigns—2,000 signers on an 1845 petition and more than double that on a petition the following year—asking the Massachusetts state legislature to cap the work day in the mills at 10 hours.
"They didn't stop there. They organized chapters in other mill towns in Massachusetts and New Hampshire. They published "Factory Tracts" to expose the wretched conditions in the mills. They testified before a state legislative committee.
"What's more, they campaigned against a state representative who was one of their strongest opponents and handily defeated him.
"So what did the Lowell mill girls really win? In the short term, not much. That's how it often is with the first pioneers in social justice movements. Both of their strikes were crushed. And the only victory they won in their 10-hour workday campaign was pretty hollow. In 1847, New Hampshire became the first state to pass a 10-hour workday law—but it wasn't enforceable.
The AFL-CIO website cited the following sources regarding the Lowell Factory Girls Association:
Foner, Philip S. (editor),
The Factory Girls. University of Illinois Press, 1977. Howe, Daniel Walker,
What Hath God Wrought: The Transformation of America, 1815-1845.Oxford University Press, 2009. Eisler, Benita,
The Lowell Offering: Writings by New England Mill Women, 1840-1845. J.B. Lippincott, 1977. Dublin, Thomas, "The Lowell Mills and the Countryside: The Social Origins of Women Factory Workers, 1830-1850," in Weible, Robert; Ford, Oliver; and Marion, Paul (editors),
Essays from the Lowell Conference on Industrial History, 1980 and 1981. Lowell Conference on Industrial History, 1981.

Jeremy Norman Collection of Images - Creative Commons
Cover of the September 1845 issue of the Lowell Offering, published by women working in the Lowell mills.