Is there a limit to the money I can carry with me (in my suitcase) at the San Francisco, California, United States of America airport?
If so, which is that limit? I will depart from SF.
There is no limit to the amount of cash you can carry in the United States. However, some caveats apply.
First, if you (where you is either a single person or a group of people traveling together) are carrying more than $10,000 USD in currency (including foreign currency) or negotiable monetary instruments in or out of the United States, you must declare it. Remember that this rule applies both entering and leaving the United States; even though you probably will not see a US Customs officer when leaving, the declaration is required and you must go to the Customs office. There are harsh penalties for failure to declare currency, so it's important to follow the procedures.
Second, civil asset forfeiture is, while not incredibly common, something that can happen. If the police believe that your cash, even if less than $10,000, could be associated with crime, often with little to no evidence, they can seize it and you'd have to go to court to try to get it back. Since most legal business doesn't involve carrying that much cash around, traveling with significant amounts of money could arouse suspicion. While there are a number of ongoing efforts to reform these laws and police procedures, it is a risk, and not carrying large amounts of cash is a way to address that risk. If you must travel with a significant amount of cash, the authorities may want to know where it comes from, so carrying documentation that demonstrates its lawful origin may be helpful.
Lastly, there's the risk of theft or loss. Americans don't typically carry large amounts of cash; we often use bank transfers, electronic payments, and even plain old fashioned paper checks. If possible, I'd recommend leaving the money in the bank and transferring it as needed.
Also remember that the country you are bringing the money to may have restrictions or declaration requirements, and that any country you are transiting through may also impose requirements. You'll need to comply with any relevant laws in the US, transit countries, and your destination.