The answer to this question is very straightforward. It does not matter whether your attend college in the same state or across the country. It doesn't even matter whether your mailing address is listed in the location of the college. The only question which needs to be answered is what the registration for the vehicle says.
Insurance companies look at the zip code where a vehicle is registered to determine the risks of insuring it. To do this, they use the zip code shown on the registration, which should always match your primary residence. Even if you are away at college, your home is usually going to be your primary residence.
If you change your primary residence to your address at college, then your car insurance will need to be changed as well. As a rule, your primary address is where your car is parked at night and most likely where all of your bills and other official correspondence are sent. In fact, state laws require you to change your driver license if you are going to reside in a new location for any extended period of time. This requirement applies to college students, but there is a way to avoid changing your insurance.
To circumvent having to change your insurance because of college, register your car in your parent or guardian's name, and use their address as the zip code for your car insurance. This will allow you to receive mail at college without paying the cost of car insurance in the new location. In general the risk of accidents is higher in the area around a college, based on the statistics that younger people are more likely to be involved in accidents, and there are more young adults in a college area.
Another benefit of the car being registered by a parent is that car insurance quotes are lower for someone over 25, so if you haven't reached 25 yet you will be able to pay much lower rates by being listed as driver on the policy rather than as the actual policy owner. The drawback to this is that you would have to give up legal ownership of the vehicle, at least until you graduate from college. Learn about other ways to get cheap car insurance quotes.