The issue of jurisdiction is less complex when there just two individuals such as when two cars collide. The issue of jurisdiction gets more complicated if one or more of the defendants is a corporation. Many corporations have a: A state of incorporation. This is usually done for financial reasons. A principal place of business. This is where their headquarters are. Headquarters may be different from the incorporation site. Different places they do business. These are the states where the corporation has offices. They can also be states where the corporation works with any customers, where the corporation works with vendors, or where the corporation does their marketing. Since most every corporation uses the Internet, which is accessible in every US state, there’s an argument that corporations do business in every state. Jurisdiction, at its core, is a question of fairness. In considering whether a defendant should be subject to the jurisdiction of an Illinois court, jurisdiction generally requires considering: The burden on the defendant. If the defendant already lives in Illinois, there isn’t a burden to hear the case in Illinois. If the defendant lives in Alaska, then coming to Illinois would be a burden – unless the defendant regularly visits Illinois. The state’s interest in resolving the dispute. For example, if all the victims of an accident live in Illinois, then that favors hearing the case in Illinois. The most efficient way to resolve the dispute. If, for example, there are many different victims and defendants, but Illinois is the most central location, that favors hearing the case in Illinois. Jurisdiction questions get more complicated if there are multiple plaintiffs and/or multiple defendants. If there are hundreds or thousands of victims, then a class-action may be required – which complicates the question of jurisdiction even further.