In Wisconsin, undocumented immigrant workers contribute significantly to the workforce, performing labor that often goes unseen. But the exact number has proven difficult to determine. 

From outdated and cautious estimates to a lack of monitoring by state agencies, it is difficult to say for certain how many immigrants without legal status work in each industry. Quantifying the undocumented population through surveys and studies is also a challenging task. The U.S. Census doesn’t ask about or estimate the number of undocumented immigrants. The Department of Homeland Security estimates the U.S. total at 11 million as of 2022.

An estimated 70,000 undocumented immigrants live in Wisconsin, about 47,000 of whom are employed, according to the nonpartisan Migration Policy Institute.  About two-thirds of those had lived in the U.S. for 10 years or more. But that information is now over five years old.

The top industries that employ undocumented workers in the state are: 

Manufacturing — estimated 11,000 workers. 

Professional, scientific, management, administrative and waste management services — estimated 8,000 workers.

Accommodation and food services, arts, entertainment and recreation — estimated 5,000 workers.

Construction — estimated 5,000 workers. 

Agriculture — estimated 5,000 workers.

A 2023 UW-Madison School for Workers survey found that over 10,000 undocumented workers perform around 70% of the labor on Wisconsin’s dairy farms. “Without them, the whole dairy industry would collapse overnight,” the researchers concluded.

This finding sparked a public debate in the wake of stricter immigration policies over the unseen, yet essential work that immigrants without legal status provide to the state’s major dairy and farming industries. 

“Obtaining accurate counts of undocumented populations is inherently challenging due to their non-legal status and potential reluctance to participate in official surveys,” said Alexandra Guevara, spokesperson for Voces de la Frontera, a Wisconsin-based immigrant rights organization. 

To complicate matters, state agencies like the Department of Administration and the Department of Public Instruction don’t keep records of the number of undocumented immigrants and workers in the state. DPI lacks this data because public schools do not ask about immigration status. 

In 2018, undocumented immigrants in Wisconsin paid an estimated $157 million in federal taxes and $101 million in state and local taxes, totaling nearly $258 million, according to the American Immigration Council. That estimate dropped slightly to a total of $240 million in federal, state and local taxes as of 2022. 

Undocumented workers make up a large percentage of the workforce in child care and domestic housework. They tend to make up a smaller portion of health care employees and are mainly employed in roles like housekeeping or janitorial and food service in both nursing homes and hospitals, according to Guevara. 

National estimates suggest that undocumented workers make up between 30% and 50% of the meatpacking workforce, according to the University of Michigan. Guevara said it is probable that Wisconsin, a major hub for meat and cheese production, follows this trend.

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How many undocumented people live and work in Wisconsin? is a post from Wisconsin Watch, a non-profit investigative news site covering Wisconsin since 2009. Please consider making a contribution to support our journalism.