US citizen lost passport, stuck in Canada without a passport

Since this is a straightforward 'US passport lost abroad question', this is what you should do, the easiest method:

What should a U.S. citizen do if his/her passport is lost/stolen abroad?

You will have to replace the passport before returning to the United States. Contact the nearest U.S. embassy or consulate for assistance. Contact information for U.S. embassies and consulates is also available in our country information pages. Ask to speak to the Consular Section to report your passport lost or stolen. If you have been the victim of a serious crime, be sure to tell a consular officer about it as soon as possible so we can provide appropriate assistance. If you are scheduled to leave the foreign country shortly, please provide our consular staff with the details of your travel. We will make every effort to assist you quickly. You will also be directed to where you can obtain a photo for your replacement passport. In most cases, you will need to get a passport photo prior to your arrival at the consular section.

If you are notified by a relative or friend traveling abroad that his/her U.S. passport has been lost/stolen, you may wish to contact the Office of Overseas Citizens Services, U.S. Department of State in Washington, D.C, at 1-888-407-4747. That office will be able to help you put your friend or loved one in touch with the closest U.S. embassy or consulate. Your relative/friend must apply in person for a new passport at the U.S. embassy or consulate

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The documentation requirements for US citizens to enter the US are mentioned on the CBP website.

• If you're traveling by air you definitely need your passport. Or a NEXUS card if coming from Canada.
• For land or sea travel you can use other alternates: if he is under 15 he can use his original birth/naturalization certificate.

EDIT: For your ease the Ottawa Embassy has the following contact details:

U.S. Embassy Ottawa

490 Sussex Drive Ottawa, Ontario, K1N 1G8 Canada

Telephone: +1 613 688 5335

Emergency After-Hours Telephone: +1 613 238 5335

Fax: +1 613 688 3082

OttawaACS@state.gov

For other consulates go to this link

There are two issues here:

1. Will the Canadians let you board an international flight without a passport or NEXUS card. The answer here is pretty definitely no. The airline company could get fined severely for doing this, so a gate agent is not likely to let your son through -- unlike for domestic flights where they might take pity on a kid.

2. Will USA immigration let you in without a passport or other government-issued documentation such as a REAL-ID driver's license or NEXUS card: Usually, but expect a thorough and perhaps delayed vetting process. They are required to let American citizens in, but they are allowed to hold you in a holding cell (for hours or even days) until they're satisfied that you are a USA citizen or refuse you if they are not satisfied. Anyone can photoshop an image of a passport or birth certificate on their laptop and verification can take longer than you might expect if the DHS and State computer systems are feeling ungracious towards each other, which can happen.

Given the latter situation, your son's best bet if he can't get an emergency replacement passport at the American consulate in Canada, is to go to a land crossing and try to cross the border to the USA there. Tell him to bring as much documentation as he can. Tell him to expect a very long delay so he should eat a hearty meal and go to the bathroom before presenting himself (and carry snacks, water, and a physical book to read). Sometimes they'll let people through in 15 minutes, but these days it might take much longer.

As a US citizen you cannot be denied entry to the United States. Therefore the fastest way of getting back home is to simply present yourself at a land crossing, where CBP officials will be forced to accommodate your request to enter the country, regardless of whether or not you have your passport. Having a scanned copy of your birth certificate and passport should be sufficient, but bring in any additional documentation you might have to prove your identity, such as your drivers license or another form of State ID.

The only tricky question is how to actually reach the US border. If you have a car available you can simply drive yourself to the border. Second best option would be to ask someone for a favour and have them drop you off. Finally, you can use public transport to reach the US - Travel.SE provides a fantastic guide listing all the options for doing so.

Once you've crossed the border and reached the US you would potentially have an issue with getting on a plane back home, as the TSA usually requires you to have government-issued ID to get on a domestic flight. But there are likewise workarounds for people who have lost their ID, so it can be taken care of as well.