If we look back in the history of the United States; States, Counties, and Cities were formed based upon transportation – just like growth patterns form today. When the 13 original colonies were formed, which later became the first states of the US, the counties were sized so that the farmers at the furthest out point from the County seat (which is in the geographic center of the county) could ride on a horse or in a horse drawn buggy from their farm to the county seat and back in 1 day. If you look at the counties in Georgia, most have distances to their edge borders that are no more than 10-12 miles. There are some that are smaller and larger but this seems to be a recurring distance. This was important because all of your government services were in the County seat and so in a 1 day trip a farmer could get to town and back to take care of numerous business activities at one time. Because of this, the County seat became the hub of commerce for the county. It was very difficult to travel in this era so the County seat became the most important business community for the County. The County seat is where you could find the courthouse, dry goods store, hardware store, doctor, drug store, markets, lawyers, hotels, etc. There were smaller communities and towns with one or a few of these services located in the county, but the County seat was definitely the main commerce hub. Some towns grew even bigger if they were located on a rail line or especially if the town was located at a major rail crossing.
As transportation changed from horse and rail to the automobile, growth patterns changed. As a society we became more mobile and it became more convenient to have services that were located further distances from where we lived. Also, as the industrial revolution occurred, the need to separate dirty businesses from residences created the zoning we have today. This lead to the common separation of uses that occurs in our suburbs today. Some will say that the desire to separate dirty industrial uses from residences caused the suburban sprawl that has occurred today. This is true to some degree but it is not the whole truth. Proponents of New Urbanism today cite instances such as the butcher that lived above his shop in a downtown area. They will tell you that because he just walks down to work and could, in the past, walk to a drug store, grocery store, etc. and meet his daily needs without the need to drive anywhere. This is also true, but they will not tell you that that butcher like most in the US was working and saving to provide a better life for himself and his family. They will not tell you that the butcher as soon as he could save up enough money would leave that upstairs unit to buy a house on the outskirts of town for his family to have a better life. The butcher like most in the US today was looking for a better life and living above his shop was a way to do that, not the life he wanted to live.
Because transportation and development patterns have been changing since this country was formed, the states after the 13 original colonies utilize the Public Land Survey System, not the metes and bounds system of the original 13 colonies. Without going into detailed description the major reasons for moving to the Public Land Survey System was because of easier and better records and better transportation. There was no longer the need for the 1 day horse and buggy ride mentioned above.
As an example of the difference in County sizes – Georgia has 159 counties with an average size of 240,000 acres. Colorado has 64 counties with an average size of 1,040,000 acres. The growth patterns were beginning to change as transportation improved.
Today, most communities do not revolve around the County seat town anymore. With the increase size of metropolitan cities, improved transportation, and improved technology, people now choose where they want to live based upon a larger geographic area than they could in the past. In fact if you look at metro regions, the large city in the middle is synonymous with the County seat in the past driving the economy of the region.