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Mail Services


Mail Services receives, sorts, processes, collects and distributes mail and courier packages for the campus community. Services include a contract station post office, FedEx ship center, and mail distribution center. We also manage bulk mail, non-profit indicia, postage dues, and business reply. Please consult with us prior to any mail-piece design to assure your mailing is within postal and print regulations and to determine if your mailing qualifies for bulk or non-profit discounts.

Post Office

Hours: 8:30 a.m.–4:30 p.m. (open during lunch)
Location: Keith Spalding Building - Room 104 • (626) 395-6371

Mail Services operates Caltech's post office (contract station #626). We service the campus community, local neighborhood, and businesses within a few mile proximities of the campus. The post office provides the most common services and products including sales of stamps, postcards, shipping supplies, domestic and international priority, express, certified, and insurance. Vacation mail hold and mail forwarding are also available.

Official Address Format

Mail Center

All incoming mail from the United States Postal Service and express overnight couriers FedEx, and DHL (under 50 lbs.) should be addressed to:

1200 E. California Blvd.
Pasadena, CA 91125

In addition, all incoming mail and packages should include recipients name, mail code, and department to insure delivery. Be sure to keep your on-line directory address updated.

Central Receiving

All incoming packages from FedEx Ground, UPS, and express overnight couriers FedEx and DHL (over 50 lbs.) should be addressed to:

391 S. Holliston Ave.
Pasadena, CA 91125

In addition, packages should include the recipient's name, delivery code, and department name to assure timely delivery.

Expect a possible delay for any incoming 1st class or higher classification mail (priority, express overnight) lacking adequate addressing information, (for security and safety reasons), as the mail or package has to be manually looked-up in the campus directory for proper routing. Lower class mail lacking complete address information including mail code (MC #or MSC #) and/or department name (standard, bulk, non-profit, etc.) will be discarded/recycled.

Mail Distribution Center

Hours: 8:30 a.m.– 4:30 p.m.
Location: Keith Spalding Building - Room 104

Mail is received from the postal service twice per day at 6:00 and 8:00 a.m. Mail is sorted and ready for distribution or pick-up daily between 8:00 and 10:00 a.m. Mail is also metered throughout the day and distribution takes place between 8:00 a.m. and 12:00 p.m. to over 128 mail stops once per day. FedEx leaves campus daily at 4:00 p.m. while the United States Postal Service departs at 4:30 p.m.

Collection Schedules

(Please see our Collection Schedule page for locations and times.)
Last p.m. collection for stamped mail, mail to be metered, and FedEx which needs to leave campus at end of the day.

FedEx Shipment Center

Hours: 8:30 a.m.– 3:00 p.m.
Location: Keith Spalding Building - Room 102 • (626) 395-6008

Mail Services operates a FedEx ship center for time sensitive documents and packages requiring traceability and overnight delivery. Our high annual volume allows our customers to benefit from discounted shipping rates (10-30% off published rates). Our mail clerks can pick up your mailing (under 50 lbs.) at your departments mail stop. Deadline for overnight express is 3:00 p.m.

Mail Tips for Work and Home

When Sending Mail

  • Always include name, full address and return address, double check spelling of names, addresses, and titles.
  • Avoid the use of excessive amounts of tape or improper packaging. Alert the addressee prior to sending out your packages.When

When Receiving Mail, Ask Yourself

  • Is the mail from someone you do not know?
  • Do you recognize the return address?
  • Is the mail sealed with excessive tape or postage?
  • Does it look stained or soiled?

If You Receive Suspicious Mail

  • Do not shake or sniff it!
  • Isolate it by covering or place in a sealed envelope or plastic bag. Keep others away from the area.
  • If on campus, contact security at x5000 or (626) 395-5000.
  • If at home, call 911 or your local law enforcement authorities.
  • Wash your hands for 5 to 10 minutes with soap and water.

Departmental Campus Mail

All departmental intra-campus mail should have the recipient's campus recognized name (in the Campus Directory) and mail code (MC#). If you are using a recycled campus/JPL envelope, cross out the last recipient's name and provide the new recipient's name and current mail code. The mail piece will be delivered on the next scheduled delivery time.

JPL Mail

All mail addressed to JPL should bear the recipient's name and mail code. JPL courier delivers to Campus Mail Services daily at 10:00 a.m. All mailings received for JPL prior to 10:00 a.m. will be dispatched back to JPL for their afternoon delivery. All mail received from JPL for campus departments will be distributed on the next scheduled delivery time.

Personal Mail

Mail Services is responsible for handling Institute related mail and student mail. Our service should not be used for personal mail. We handle the personal mail of undergraduates residing on campus whose zip code is 91126. All others should receive personal mail at off-campus addresses. We are not responsible for non-Institute related stamped personal mail left for pickup with departmental mail, although we will handle it as a courtesy.