It's an American truism that school starts later in the north than it does in the south. Some school systems in the southeast began classes yesterday, while most northern schools won't begin until the day after Labor Day. There is nowhere in the country that provides a starker view of this north vs. south "first day of school divide" than Virginia.

Virginia is a weird place to live. Having grown up in Lake Ridge, a bursting-at-the-seams suburb of Washington, I always heard that northern Virginia wasn't "real Virginia;" the capital's suburbs are more northern than southern since nobody in northern Virginia is from northern Virginia. The divide is stark and abrupt. The short drive up the Prince William Parkway from Lake Ridge to Manassas is a treat because you go from sprawling subdivisions to miles of trees to farmland, all in about a dozen miles.

Get out of the suburbs, or at least west of I-95, and there's nothing. Well, "nothing" compared to what most are used to. It's open fields, rolling mountains, and sparsely populated towns aside from the occasional Roanoke or Charlottesville.

Virginia is divided — culturally, politically, geographically — and the first day of school is no different.

Here are the first days of school for Virginia, Maryland, and Washington D.C. for 2013. The western and southwestern part of the Virginia more closely relates to the rest of the southern United States, starting school towards the middle of August, while the eastern part of the state mimics the traditional northern schedule.

The 2013 school year's earliest start date was Wise County (dark red) at August 8, and the latest start date was Montgomery County (VA), starting on September 4.

One trend that stands out appears when we look at the population density map of Virginia. Counties that are more densely populated generally have a later start date than those that are more sparsely populated. Of course, this is just population density (people per square mile) and not raw population numbers; the northern and eastern part of the state are home to many more people than the southern and western half of Virginia.

There is one big factor involved in Virginia starting school the day after Labor Day rather than in August, popularly known as the "Kings Dominion Law." If you're not familiar with Kings Dominion, 1) lucky you, and 2) it's an amusement park on I-95 near Fredericksburg (you've probably seen the Eiffel Tower replica if you've driven the interstate) that is a big tourist destination for people in the Mid-Atlantic.

The Kings Dominion Law was passed back in the 1980s and it mandates that schools in Virginia don't start until after Labor Day so that the state can get the maximum amount of tourist dollars before everyone up north has to head back to school themselves. It allows tourist traps like Kings Dominion, Busch Gardens, and heavily-visited beaches to stay open through the busy Labor Day weekend rather than having to close up a few weeks early and miss out on millions of dollars in revenue for lack of teenage employees.

In light of the fact that every attempt to repeal the Kings Dominion Law has failed in Richmond, counties have to rely on getting waivers from the state government in order to start school in August. Most counties have exercised the waiver option except for those along and east of I-95, where northern tradition and/or tourist dollars prevail.

I included Maryland and D.C. on the map for a good reason. Interestingly enough, in the much more developed and decidedly less southern Maryland and Washington D.C., students start school in August rather than in September. For the most part this change is fairly recent, only taking place within the last decade or two.

What was once a northern tradition of starting school the day after Labor Day is quickly becoming a thing of the past, and Virginia is ground zero for the cultural shift.

[Images via Arlington County / author / Rand McNally]