OF POPULATION COMPUTATION
FOR 1950, 1960, 1970, 1980, 1990 and 2000
Issued April 2001
U.S. Census Bureau
U.S. Department of Commerce
Washington, DC 20233
This documents the procedure used to compute the population center of the states and the District of
Columbia of the United States in 1950, 1960, 1970, 1980, 1990 and 2000, based on counts of population
obtained in the corresponding decennial censuses. Although Alaska and Hawaii became states during the
1950s, for historical comparability some computations may not include them.
This document provides information for many U.S. Census Bureau data users, some of whom have
sought this information in unpublished form in the past. It is not meant to champion the gravity center of
population concept as a pre-eminent measure for analyzing population distribution and change. Because
there are many ways of measuring distribution, as well as change, this documents the method long used by
the Census Bureau to determine the center of population.
Computation of Centers
The concept of the center of population as used by the U.S. Census Bureau is that of a balance point.
That is, the center of population is the point at which an imaginary, weightless, rigid, and flat (no elevation
effects) surface representation of the 48 conterminous states and the District of Columbia (or 50 states as
appropriate to the computation) would balance if weights of identical size were placed on it so that each
weight represented the location on one person. This is a somewhat technical point in that this is different
from the use of the term "center of population" to denote a place where half the population is to one side and
half to the other side, likewise, above and below. Such a median population point, in a certain sense, is a
center of population; it is not, however, the method used for thi