Sort Hub
A sort hub (also called a superhub, distribution hub, or sort center) is a large-scale facility where parcel carriers sort packages by destination. Hubs like FedEx's Memphis Superhub process millions of packages nightly, making them both the engines and the capacity constraints of express shipping networks.
Definition
Sort Hub is a central facility in a hub-and-spoke transportation network where packages from multiple origins converge, are sorted by destination, and are dispatched toward their final delivery points. Sort hubs use sophisticated automation—conveyor systems, optical scanners, and automated sorting—to achieve throughput rates of hundreds of thousands of packages per hour.
Why Sort Hubs Matter
Sort hubs are what make overnight and express delivery possible:
- Consolidation efficiency: By concentrating all packages at a central point, carriers can build full loads for every destination
- Service coverage: A single hub can connect thousands of origin-destination pairs that wouldn't justify direct service
- Capacity ceiling: Sort hub throughput is fixed by building size and automation speed—this creates hard capacity limits during peak periods
Major U.S. Sort Hubs
FedEx Memphis Superhub
The world's largest cargo hub, located at Memphis International Airport. Memphis processes the majority of FedEx Express volume, with over 150 aircraft movements nightly during the sort window.
UPS Worldport (Louisville)
UPS's global air hub in Louisville, Kentucky. Worldport sorts over 400,000 packages per hour using 155 miles of conveyor belts. It's the largest automated package handling facility in the world.
Amazon Air Hub (Cincinnati)
Amazon's primary air cargo hub at Cincinnati/Northern Kentucky Airport. Part of Amazon's strategy to reduce dependence on UPS and FedEx forlinehaul transportation.
Regional Ground Hubs
In addition to air superhubs, carriers operate ground sort facilities in markets like Chicago, Dallas, and Los Angeles that sort packages for ground transportation networks.
Why Sort Hubs Become Bottlenecks
The same centralization that enables efficiency also creates vulnerability:
- Fixed throughput: A sort hub can process X packages per hour. When volume exceeds X, packages wait for the next sort cycle, adding 24 hours to transit
- Time windows: Express sorts must complete within tight overnight windows to meet morning delivery commitments. There's no "second shift" option
- Single point of failure: Weather, equipment failures, or labor issues at a superhub affect the entire network
- Peak demand spikes: DuringQ4 peak, volume can exceed hub capacity for days or weeks at a time
Common Misconceptions
- "Carriers can easily add hub capacity." Building a new superhub takes 5+ years and billions of dollars. Expanding existing hubs is constrained by airport and land availability. Capacity expansion is measured in years, not weeks.
- "All packages route through superhubs." Ground services and regional deliveries often bypass air superhubs, routing through regional ground hubs or direct linehaul instead.
- "More automation means unlimited speed." Automation increases throughput but has physical limits. Package jams, scanner misreads, and dimensional exceptions all create slowdowns that automation can't eliminate.