アメリカ合衆国ジョージア州における円形の自治体境界

抄録

About sixty-four per cent of the existing incorporated places in Georgia have circular or arcuate corporate limits. The use of the circular boundary first appeared in northeastern Georgia in the first decade of the nineteenth century. It spread into middle Georgia, western and southern Georgia during the nineteenth century along with population expansion into these areas. The present distribution pattern of the circular and arcuate places was almost completely established by 1920.
By 1830, all circular places were located in the Piedmont and they were separated by no more than two intervening counties. These places defined the courthouses as the center of the circular limits. Between 1831 and 1860, circular places spread into the western Piedmont, northwestern and western Georgia. This pattern shows outward spread from northeastern Georgia. Circular boundaries became common among municipalities in the Piedmont. Courthouses accounted for more than fifty per cent of the center points of the circular limits.
Between 1861 and 1890, the adoption rate of a circular boundary reached to ninety per cent. Circular places expanded into western Georgia and the Coastal Plain. This process, too, was outward expansion of adoption of circular boundaries. The adoption of circular limits, however, was characterized by small local places. Since Georgia had small minimum population requirement for incorporation, many small places were incorporated during this period. The main function of these places was a commercial center. A small town consisted of a compact commercial core and surrounding residential areas. The length of a radius of a circular limit was arbitrarily set so as to encompass built-up areas and outlying areas. This simple method of fixing a boundary was widely used throughout Georgia between 1861 and 1890.
Between 1891 and 1920, circular places spread into the Coastal Plain along with the creation of towns in expanding agricultural lands. As circular boundaries were adopted by local places throughout Georgia, center points of the boundaries were diversified. Between 1861 and 1890, railroad stations were predominant in the central points. After 1891, the use of intersections of major roads, and specified stores as centers of circular limits increased.
The use of the circular boundary appears to have been very efficient for small municipalities because circular limits were described only in terms of a fixed center point and arbitrary length of radius without actual field survey.