Car insurance is a necessary expense for drivers, but the cost can vary significantly depending on several factors. One factor that can have a surprising impact on your premium is your zip code.

Most Americans know their ZIP code by heart. They type it into online forms, scribble it on envelopes and memorize it as part of their address. But not everyone knows the original meaning of the term.

Your ZIP code affects car insurance because insurers use it to measure risk in your area. Accident rates, theft, vandalism, and severe weather damage vary by location, so car insurance companies ...