The American Postal Workers Union (APWU) is the largest postal union, representing more than 260,000 USPS career employees primarily in the Clerk, Maintenance and Motor Vehicle Services crafts.

The National Association of Letter Carriers (NALC), the second largest postal union, represents about 222,000 career employees. NALC members deliver mail to residences and businesses on city delivery routes.

National Rural Letter Carriers’ Association (NRLCA) career and part-time relief workers deliver mail to residences and businesses on rural delivery routes.

The National Postal Mail Handlers Union (NPMHU), a division of the Laborers’ International Union of North America, represents nearly 58,000 career employees engaged in the bulk transfer, loading and unloading of mail.