Decentralization, the intrametropolitan movement of people and activity away from dense centers toward less developed suburbs, occurs when dispersive forces are greater than agglomerative forces for any metropolitan area. Two mathematical tools, the regional dispersion index and the Hoover index, are used to measure the movement of population, employment, and retail activity in the Hartford, Connecticut, metropolitan region from 1900 to 2000. The approach used differs from other research in that it does not assume a parametric density function, and it allows decentralization for a multicentered region to be measured. Between 1900 and 1930, population concentrated toward Hartford and other regional centers. The trend reversed around 1940, and for the remainder of the century population decentralized away from both Hartford and regional centers. Economic activity bore the same overall pattern with a lag. The results presented here are consistent with existing theories of decentralization and previous empirical work.