Here are the top 30 USPS hubs (sorting and distribution centers) in the United States, based on the volume of mail they handle:
- Chicago, IL (O’Hare International Airport) – Chicago Network Distribution Center (NDC)
- Los Angeles, CA – Los Angeles NDC
- New York, NY – Morgan P&DC
- Dallas, TX – Dallas NDC
- Memphis, TN – Memphis NDC
- Atlanta, GA – Atlanta NDC
- Houston, TX – North Houston P&DC
- San Francisco, CA – San Francisco P&DC
- Denver, CO – Denver NDC
- Philadelphia, PA – Philadelphia NDC
- Seattle, WA – Seattle NDC
- Detroit, MI – Detroit NDC
- Miami, FL – Miami NDC
- Pittsburgh, PA – Pittsburgh NDC
- St. Louis, MO – St. Louis NDC
- Cleveland, OH – Cleveland NDC
- Boston, MA – Boston NDC
- Charlotte, NC – Charlotte NDC
- Kansas City, MO – Kansas City P&DC
- Phoenix, AZ – Phoenix P&DC
- San Diego, CA – San Diego P&DC
- Cincinnati, OH – Cincinnati NDC
- Orlando, FL – Orlando NDC
- Indianapolis, IN – Indianapolis P&DC
- Salt Lake City, UT – Salt Lake City NDC
- New Orleans, LA – New Orleans NDC
- Baltimore, MD – Baltimore P&DC
- Portland, OR – Portland NDC
- Sacramento, CA – Sacramento P&DC
- Milwaukee, WI – Milwaukee P&DC