Nigeria is most often the nation referred to in these scams, they originate in other nations as well.
An advance-fee fraud is a form of fraud and one of the most common types of confidence tricks. The scam typically involves promising the victim a significant share of a large sum of money, in return for a small up-front payment, which the fraudster requires in order to obtain the large sum. If a victim makes the payment, the fraudster either invents a series of further fees for the victim or simply disappears.
The number “419” refers to the section of the Nigerian Criminal Code dealing with fraud, the charges and penalties for offenders.