Recognition of 13 newly defined standard metropolitan statistical areas (SMSA's) and the addition of 20 counties to established SMSA’s between October 18, 1963, and May 1, 1967, by the Bureau of the Budget brought the 1960 population in standard metropolitan statistical areas to 118.2 million, or 65.9 percent of the population of the United States (table A). Two areas, Winston-Salem and Greensboro-High Point, were consolidated as the Greensboro-Winston-Salem-High Point, N.C., SMSA in this period. In addition, three cities in areas as defined in 1960—Warwick, Rhode Island; Everett, Washington; and Orange, Texas—were designated as central cities. The 13 added areas were recognized because the Bureau of the Census had found that the population of the principal central city had reached the minimum of 50,000 or two adjoining cities had qualified as “twin cities.”

Since the publication of the 1960 Census reports, the number of SMSA’s has increased by 16 to 228. The additions and revisions of SMSA’s added 99 counties, and in the New England States, 37 towns, to the areas as shown in the 1960 Census reports. The additional areas and the revisions of existing areas have resulted in the addition of 5.3 million persons to the metropolitan population, 1.2 million of whom were living in the central cities and 4.1 million in the outlying areas.