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You have received a “Processed Through Facility ISC Chicago IL (USPS)” tracking update.

What does this mean exactly? What is the ISC Chicago IL and how close is your mail from delivery?

Let’s take a look…

“Processed Through Facility ISC Chicago IL (USPS)” – Meaning

“Processed Through Facility ISC Chicago IL (USPS)” means the mail item has arrived at the Chicago International Service Center and it has been scanned. Before being dispatched from the ISC it will undergo customs clearance checks.

What is ISC Chicago IL (USPS)?


The International Service Center (ISC) in Chicago is a USPS sorting facility based within the wider O’Hara International Airport complex.

Inbound and outbound international mail items are processed within the service center, with customs clearance checks also taking place.

ISC Chicago IL is the main USPS processing center of its kind in the midwest.

USPS also has major international processing hubs in Miami, Los Angeles, New York, and San Francisco.

What Happens Inside ISC Chicago IL (USPS)?

ISC Chicago IL (USPS)

The “Processed Through Facility ISC Chicago IL (USPS)” update is actually quite misleading.

The mail item has not in fact been processed at this stage, it has merely arrived at the center. This could be outgoing mail traveling overseas, or international mail entering the USA.

Essentially, the alert signifies to the recipient and sender that the consignment has entered the ISC.

Before it leaves Chicago ISC the shipment will be subjected to the customs clearance process.

This means that customs staff work alongside USPS within the ISC to check incoming and outgoing shipments.

Once the shipment has been cleared it will be passed on to USPS (if entering the USA) or the linehaul carrier (if being shipped to another country) for the next stage of the journey.

Is ISC Chicago IL (USPS) a Customs Facility?


The ISC Chicago IL is primarily a sorting center as far as the role of USPS.

However, as already mentioned, the United States Customs and Border Protection (CBP) is at work within the same complex.

Needless to say, the two organizations have distinct roles in the processing of incoming and outgoing shipments.

The CBP’s sole responsibility is to inspect all international packages entering or exiting the USA.

Customs staff will check the contents of shipments to ensure no prohibited items, (foods, animals, drugs, and counterfeit goods for example) are contained within.

USPS on the other hand is responsible for the sorting and delivery of items entering the USA, (as well as the appropriate dispatch of items leaving the USA).

So yes, a shipment will go through the customs process at ISC Chicago IL (USPS), however, the item is under the jurisdiction of the CBP as this happens.

How Does the CBP Check Mail within the ISC Chicago IL? 

packages on a conveyer belt

Here’s a summary of what happens when the CBP checks a package within the ISC Chicago IL facility:

  • Non-intrusive inspection techniques, i.e checks without opening the package are the first step. This will also involve relevant documentation checks.
  • Any suspicious mail items will be taken to an inspection area, for further examination by sniffer dogs and/or subjected to x-rays
  • Finally, a package will be opened for a physical inspection if required.

The U.S. Postal Service processed over 729 million pieces of international mail and parcels in fiscal year (FY) 2020, with the vast majority of shipments clearing customs with little issue.

After clearance, consignments are once again in the control of USPS who will deliver the package or hand it across to linehaul.

How Long Will my Package be at the ISC Chicago IL?

ISC Chicago IL (USPS)

The length of time a package takes to leave the ISC processing facility in Chicago varies widely.

Under normal circumstances, a small package (that is part of a single consignment), should take between 1 and 3 days to be processed through the ISC.

Bulk imports/exports can take longer due to the nature of the clearance inspection.

Also, unloading, sorting, and dispatch times should be attached to these estimates, and can see even a simple mail item be held up for a week or more.

Furthermore, if there is a problem with the shipment in terms of clearance, the processing times can take much longer.

Issues that impact processing times at the ISC Chicago: 

  • Declaration of the package contents
  • Correct and fully filled in documentation
  • Where the package has come from (i.e which country)
  • The size and weight of the package
  • Whether tax or duties are owed
  • Staffing levels (Covid staff reductions had massive impacts)
  • The volume of packages arriving (seasonal variations)

As you can see, there are many variables that can impact the time a consignment remains stuck in the ISC Chicago IL (USPS)

My Package is Stuck at ISC Chicago IL (USPS)

woman on phone complaining

If your package tracking status remains stuck within the ISC Chicago IL (USPS) facility for more than 7 days you will have grounds to contact USPS to see what the delay is.

Also, it will probably come as little consolation but you are not alone. Below are a few quotes from online forums on this subject.

There is also a Google reviews page that is full of annoyed customers that have waited several weeks and more for items to leave the Chicago ISC.

Customer Comments regarding wait times at ISC Chicago IL (USPS)

“I have had a package at Chicago ISC since May 7. Filed a report, but have heard nothing.”

“This is so unacceptable. You’re employed to move packages. Taking two months three months is just not acceptable. You are playing with peoples hard-earned money. Someone really needs to open up a news investigation about some of these customs facilities.”

“I’m waiting on two packages going through this cesspool.”

“If you look at the reviews of this place on Google, there are hundreds of people experiencing the same issues, and it isn’t just recent.”

“Having the same issue. I’ve several packages that have been stuck there for a month. I experienced this issue about a year ago. Took about three months to receive the package.”

The problems at the Chicago ISC have not gone unnoticed by policymakers either.

The USPS Office of Inspector General stated (Report Number: 21-101-R21, published May 12th, 2021), that “while conducting site visits at the Chicago International Service Center (ISC)… we found significant operational delays of international packages and safety and security risks that we believe warrant management’s immediate attention and corrective action.

What To Do if Your Package is Stuck at ISC Chicago?

girl shrugging

If you do not receive any updates after the “processed through…” alert, it can be difficult to determine whether the hold-up is due to general delays in the ISC processing or if a problem has occurred during customs clearance.

If there has been a customs clearance issue the shipper or recipient is generally alerted (via further tracking updates or an email), as to what these are.

However, as the many online comments suggest, communication as to the whereabouts of the mail item can also be scarce.

Essentially, if the tracking status does not update after 7 days you should contact USPS Customer Service to find out more.

How to Contact ISC Chicago IL

man on telephone

Customers can call the USPS International Inquiry Center at 800-222-1811 to initiate an inquiry regarding international registered, recorded delivery, insured, and ordinary parcels.

There is also a USPS ISC Facebook Page, where you can post concerns considering delays.

You may also wish to raise your complaint with the USPS Inspector General Office.

Tracking Updates Related to “ISC Chicago IL (USPS)”

tracking lots of numbers

There are a number of USPS tracking updates you can expect to see after your package has arrived at the ISC Chicago IL (USPS) facility.

This includes confirming that the customs clearance process is underway (Inbound into Customs) or has successfully been completed, (Inbound out of Customs), as well as indicators that the package has been returned to USPS and has been dispatched to another facility.

For example, the “Arrived at USPS Regional Facility”, means your package has left the ISC and arrived at a Chicago regional sorting facility and has been scanned.

You may also receive an “In Transit to next USPS Facility” tracking alert. This means exactly what it describes. The package is on its way to the next facility (or post office) closer to the destination address.

Final Words

Essentially, the ISC Chicago IL (USPS) is a major facility responsible for mail and packages coming in and out of the USA in the midwest.

In other words, if you live in this region of the United States and are sending or receiving mail to or from overseas, your item will pass through this facility.

The United States Customs and Border Protection works inside the facility to inspect shipments to ensure the safety of U.S. citizens and that laws are abided by.

Long wait times for packages coming through the ISC are unfortunately all too common, so be prepared.

2 thoughts on “ISC Chicago IL (USPS) – ALL YOU NEED TO KNOW”

  1. Every single one of them need to be fired and charged with criminal offenses. That facility is nothing but a den of vipers and thieves. The United States Postal Service as a whole is an aberration and a shit-stain on the face of mankind’s achievements.

    We can send people and goods across the face of the earth, but this pitiful excuse for a mail facility can’t manage to keep track of a parcel no bigger than a letter. I have no doubts that my package was disassembled, and passed out amongst the corrupt and drug addicted staff that frequent this facility.


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