The best way to understand the legal concept of jurisdiction is by way of example. Suppose a Pennsylvania resident is injured in a car accident on Route 202 literally 100 yards across the Pennsylvania-Delaware border within the State of Delaware. And suppose the driver causing the accident lives in Delaware. Can the injured Pennsylvania motorist sue the Delaware driver in Chester County, Pennsylvania? (Remember, Chester County, Pennsylvania is 100 yards from the scene of the accident.) The answer is probably not because the Pennsylvania court would not have in personam jurisdiction over the Delaware driver. In this example, jurisdiction means “power”, i.e., the power to force a person to answer to a civil complaint. The injured Pennsylvania driver would have to bring suit in the State of Delaware because that is where the accident occurred, and that is the State in which the defendant resides. The Delaware driver has no connection to the Commonwealth of Pennsylvania and therefore cannot be sued in Pennsylvania on these facts.
Suppose a Pennsylvania resident catches his wife cheating and wants to file for divorce. Can the husband file for divorce in the United States District Court for the Eastern District of Pennsylvania if the couple resides in the Eastern District of Pennsylvania? The answer is no. This is because the U.S. District Court does not have subject matter jurisdiction over divorce cases. Put another way, the U.S. District Court does not have the power to hear this particular type of case. A divorce case would have to be brought in a state court in the county where the parties reside.
The above examples illustrate that there are two types of jurisdiction: personal jurisdiction and subject matter jurisdiction. Personal jurisdiction is the power to exercise authority over a person; subject matter jurisdiction is the power to exercise authority over a particular type of case.
In the law enforcement arena, the concept of jurisdiction is largely territorial. With certain exceptions, a police offer is vested with jurisdiction within a specified geographical territory. Once again, in this context, jurisdiction means power: the power to enforce the law and regulate the conduct of individuals within a specified territory.
One final example: suppose a wiseguy throws a stone from a highway overpass near the Pennsylvania-Delaware border (but within the State of Delaware) and the stone crosses the state border and hits a windshield of a car in Pennsylvania. Can he be sued in Pennsylvania? Delaware? The answer is probably both States. That is because he committed a tortious act in Delaware which had a damaging result in Pennsylvania. This is enough to vest either state with jurisdiction over the miscreant.
— Kevin Palmer