Few things have been as important to the development of a strong middle class in America as the labor union. In their heyday, labor unions were an essential piece of the social fabric that helped ensure that workers could have a strong voice in getting paid fair wages, securing important benefits and ensuring safe working conditions. However, the days of organized labor wielding enormous influence are largely gone as union memberships continue to shrink in the face of an ever-shifting economy. From 1983 to 2015, union rolls shrank by nearly 3 million workers even as over 45 million more people joined the workforce, and the proportion of workers in a union was cut in half over that same period.

So, what does the face of American organized labor look like today? What unions still command the largest membership base, allowing them to influence public policy and pressure companies into making concessions?

GOBankingRates looked at the membership numbers from some 78 different unions as available through the Department of Labor and identified 30 that still have at least 100,000 members. Some of them are among the most powerful unions in the nation and have led strikes that changed America.

29. National Rural Letter Carriers’ Association

• Total membership: 114,598
• Description: United States Postal Service (USPS) mail delivery workers in rural areas
• Member of the AFL-CIO? No

21. American Postal Workers Union

• Total membership: 235,253
• Description: USPS workers other than letter carriers
• Member of the AFL-CIO? Yes

19. National Association of Letter Carriers

• Total membership: 290,315
• Description: USPS mail delivery workers in urban areas
• Member of the AFL-CIO? Yes’

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