Hi - I'm a green card holder and live in the USA but still work in Canada (a surprisingly short daily commute!) I have a SSN and file taxes in both countries though I don't earn money in the USA. My question is - when I am elderly, would I get social security benefits even though I've never worked in the USA or contributed to the US or state tax? (other than city/property taxes).
Just curious.

Are Social Security taxes witheld from your paycheck?

Working in Canada for a Canadian company, I would suspect you are accruing social security benefits there. Since you work in Canada, your employer makes deductions from your paycheck and submits them to some sort of government agency. No?

You would be eligible to receive Canada Pension benefits, as well as Old Age Security benefits, they'll mail it to your US address no problem.

If in future you were to quit your Canadian job and get a job in the US and start paying into Social Security, the years that you've paid into the Canadian coffers will be taken into account for your Social Security benefits at retirement. There is a treaty between the 2 countries.

Have a search thru their website, all the info is there http://www.hrsdc.gc.ca/en/isp/cpp/cpptoc.shtml

Thanks for the info everybody. I will get retirement benefits from my Canadian employer.