The results of an effort to develop a body of internally consistent economic data which facilitate comparison of the population, housing, employment, and income characteristics of 56 Standard Metropolitan Statistical Areas with a population of over 500,000 are reported in this publication. Part of a continuing research program on local government finances, the report was designed to fill some important gaps and provide the basis for future research efforts in this area. Development of a consistent data system required selection of a manageable number of the most relevant areas from among the current total of 231 Standard Metropolitan Statistical Areas, and adaptation of an extensive system of basic data for each of these by means of classification and coverage which permit internal comparison and, at the same time, provide historic continuity. The data include information, sometimes as current as 1967, covering the general topics: (1) location and types of major metropolitan areas, (2) population, (3) land, (4) population densities and housing, (5) employment size, composition, and trends, and (6) income and wages. Detailed information by area is given in 13 statistical tables, permitting easy comparison on any factor between the various urbanized areas. (ET)