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 A 1900 Census Office bulletin stated that in order for topographic divisions to serve statistical purposes, the lines between them must coincide with the boundaries of areas for which statistics are given separately by the census. Since the smallest available entity at that time was the county, Gannett adjusted the topographic division boundaries to coincide with county lines. To this day, one of the most basic operational rules of the Census Bureau’s geographic hierarchy is that geographic statistical entities for presenting census data must correspond to the geographic units for which the information otherwise is collected or tabulated. In delineating the divisions, he found that it was necessary to balance the different variables of geology, topography, altitude, rainfall, and temperature in order to create a physically homogeneous geographic entity enclosed by county boundaries.

Aside from Gannett’s participation in delineating geographic divisions, both for the decennial census publications from 1880 through 1900, and for historical compilations involving the 1870 statistics by county, his observations set forth in the 1900 Census Office bulletin also include the mention of geographic splits; that is, the operational subdivision of existing collection units that must serve as the building blocks for some different kind of geographic entity in a data tabulation or publication. This practice continues in selected census tabulations; for instance, the Census Bureau frequently splits other standard geographic units to provide data for entities such as incorporated places (see, “Places”).

By the late 19th Century, the geographic designations Northeast, South, Interior, and West had come to mean much the same as they do today. This general acceptance undoubtedly favored the retention of the 1880 pattern of State groupings in the Census Bureau’s statistical presentations rather than creating other combinations. Starting with the 1900 census, the statistical tables presented fewer alternative geographic groupings; instead, they made increasing use of a single, standard set of summary areas. The introductory texts in subsequent publications of the Census 6-16Statistical Groupings