Gun violence in North American is the subject of much speculation and debate, often based on limited or incomplete empirical evidence. We summarize the regulatory frameworks in Mexico, the United States and Canada, and provide statistics on gun misuse in these countries. Based on our analysis of publicly available information on sources of crime guns, we conclude that while the United States is a major supplier of illegal handguns to Canada and illegal firearms of all types to Mexico, quantifying the extent of its role, particularly in Mexico, is difficult because of data limitations. Still more difficult is to project the consequences of an effective crackdown by US authorities. If the illicit supply from the USA dried up, the criminal gangs could turn to a variety of other sources that already appear to be playing some role. A complete analysis of these issues must await more complete disclosure by the authorities of data on gun sources and trafficking investigations.