percent increase was recorded in Corpus Christi, which had a gain of 89.0 percent. Of the eight cities of 100,000 inhabitants or more in 1950 which lost population between 1940 and 1950, all but oneWilmington, Del.-were located in the Northeast. Scranton, Pa., which experienced a loss of 14,868, or 10.6 percent, led these cities in both the amount and rate of decline.

Between 1940 and 1950 there were a number of changes in the ranking of the 10 most populous cities (table 25). The three cities which ranked first, second, and third in 1940-New York, Chicago, and Philadelphia-retained their positions in 1950. The only other one of the first 10 cities to retain its position was St. Louis, which occupied eighth place. Los Angeles replaced Detroit as the fourth most populous city, and Baltimore replaced Cleveland as the sixth most populous city. Washington, D. C., became one of the 10 most populous cities for the first time, reaching the ninth position and replacing Boston, which now ranks as the tenth most populous city. Pittsburgh, which occupied the tenth position in 1940, dropped to twelfth in 1950. TABLE L.-CITIES OF 25,000 OR MORE IN 1950 THAT INCREASED BY 100 PERCENT OR MORE BETWEEN 1940 AND 1950

1 Part of township 10, Contra Costa County, annexed to Richmond in 1949. Parts of old police jury wards 3, 6, 8, and 9, East Baton Rouge Parish, annexed to Baton Rouge in 1949.

Parts of precincts 1, 2, 3, and 4, Ector County, annexed to Odessa since 1940. Part of Compton township, Los Angeles County, annexed to Compton since 1940. Parts of precincts 6, 13, 15, and 24, Bernalillo County, annexed to Albuquerque since 1947.

Parts of Liberty, Noble, and Norman townships, Cleveland County, annexed to Norman in 1948 and 1949, in 1944, and in 1940, 1944, and every year 1946 through 1950, respectively.

Parts of Compton township, Los Angeles County, annexed to Lynwood since 1940. Part of Blue township, Jackson County, annexed to Independence in 1948.

Part of Los Angeles township and Los Angeles city, Los Angeles County, annexed to Burbank in 1948.

Parts of precinct 1, Lubbock County, annexed to Lubbock in 1940, 1941, and every year 1945 through 1950.

Parts of Clark County annexed to Vancouver in 1946, 1947, 1948, and 1950. Parts of township 3, San Mateo County, annexed to San Mateo in 1945, 1947, 1948, and 1950.

Parts of township 3, San Mateo County, annexed to Redwood in 1940, 1943, and each year 1945 through 1949.

Parts of precincts 1 and 2, Tom Green County, annexed to San Angelo in 1940, 1942, 1947, 1948, and 1949 and in 1949, respectively.

Unincorporated Places

Of the unincorporated places for which boundaries were delinested by the Bureau of the Census, 1,430 were found to have 1,000 inhabitants or more (table K). There were 3,565,496 persons living in these unincorporated places, 1,570,769 of whom were living in the 1,029 places of 1,000 to 2,500 inhabitants.

Variations in local practice with respect to incorporation and in the extent to which densely settled areas outside incorporated places were included in urban-fringe areas affect the number of unincorporated places in a given State. Three States-Delaware, lows, and North Dakota-and the District of Columbia had no unincorporated places. In the remaining 45 States, the number of unincorporated places ranged from 1 in Minnesota, South Dakota, and Wyoming to 143 in Pennsylvania. The number of persons living in unincorporated places varied from 1,727 in

Incorporated and Unincorporated Places in Alaska, Hawaii, and Puerto Rico

There were 27 incorporated places in Alaska in 1950, 9 of which were incorporated as cities and 18 of which were incorporated as towns. The most populous of the incorporated places was the city of Anchorage, which had a population of 11,254. Three additional places-Fairbanks city, Juneau city, and Ketchikan town-had more than 5,000 inhabitants. The 27 incorporated places had a combined population of 45,630, or 35.5 percent of the population of the Territory. In addition to the incorporated places in Alaska, the Bureau of the Census enumerated separately all places recognized locally. All such places with 25 inhabitants or more are reported as unincorporated places.

There are no incorporated places in Hawaii or Puerto Rico. The cities, towns, and villages in both Hawaii and Puerto Rico are unincorporated places which have locally recognized boundaries.

STANDARD METROPOLITAN AREAS

It has long been recognized that for many types of social and economic analysis it is necessary to consider as a unit the entire population in and around the city whose activities form an integrated social and economic system. Prior to the 1950 Census, areas of this type had been defined in somewhat different ways for different purposes and by various agencies. Leading examples were the metropolitan districts of the Census of Population, the industrial areas of the Census of Manufactures, and the labor market areas of the Bureau of Employment Security. The usefulness of data published for any of these areas was limited by this lack of comparability.

Accordingly, the Federal Committee on Standard Metropolitan Areas, composed of representatives of interested Federal agencies, including the Bureau of the Census, and sponsored by the Bureau of the Budget, established the "standard metropolitan area" so that a wide variety of statistical data might be presented on a uniform basis. Since counties instead of minor civil divisions are used as the basic component of standard metropolitan areas (except in the New England States), it was felt that many more kinds of statistics could be compiled for them than for such areas as the formerly established metropolitan districts, which were not defined in terms of counties.

Definition

Except in New England, a standard metropolitan area is a county or group of contiguous counties which contains at least one city of 50,000 inhabitants or more. In addition to the county, or counties, containing such a city, or cities, contiguous counties are included in a standard metropolitan area if according to certain criteria they are essentially metropolitan in character and socially and economically integrated with the central city.

The criteria of metropolitan character relate primarily to the character of the county as a place of work or as a home for concentrations of nonagricultural workers and their dependents. Specifically, these criteria are:

1. The county must (a) contain 10,000 nonagricultural workers, or (b) contain 10 percent of the nonagricultural workers working in the standard metropolitan area, or (c) have at least one-half of its population residing in minor civil divisions with a population density of 150 or more per square mile and contiguous to the central city.

2. Nonagricultural workers must constitute at least twothirds of the total number of employed persons of the county. The criteria of integration relate primarily to the extent of economic and social communication between the outlying counties and the central county as indicated by such items as the following: 1. Fifteen percent or more of the workers residing in the contiguous county work in the county containing the largest city in the standard metropolitan area, or

2. Twenty-five percent or more of the persons working in the contiguous county reside in the county containing the largest city

3. The number of telephone calls per month to the county containing the largest city of the standard metropolitan area from the contiguous county is four or more times the number of subscribers in the contiguous county.

In New England, the city and town are administratively more important than the county, and data are compiled locally for such minor civil divisions. Here towns and cities were the units used in defining standard metropolitan areas, and most of the criteria set forth above could not be applied. In their place, a population density criterion of 150 persons or more per square mile, or 100 persons or more per square mile where strong integration was evident, has been used.

Central Cities

Although there may be several cities of 50,000 or more in a standard metropolitan area, not all are necessarily central cities. The largest city in a standard metropolitan area is the principal central city. Any other city of 25,000 or more within a standard metropolitan area, and having a population amounting to onethird or more of the population of the principal city, is also a central city. However, no more than three cities have been defined as central cities of any standard metropolitan area. The name of every central city is included in the name of the area, with the exception that in the case of the New York-Northeastern New Jersey Standard Metropolitan Area, "Jersey City" and "Newark" are not part of the name.

Relation of Standard Metropolitan Areas to

Other Specially Defined Areas

The standard metropolitan area is one of several areas which have been specially defined for purposes of separately identifying large concentrations of population in and around cities of 50,000 or more. Other areas in this class are the metropolitan district of 1940 and the urbanized area.

Since, as described in the following section on this type of area, the metropolitan district was built up from minor civil divisions and since the standard metropolitan area is generally composed of whole counties, the standard metropolitan area ordinarily includes a larger territory than the corresponding metropolitan district. There are, however, cases in which parts of the metropolitan district, as defined in 1940, do not fall within any standard metropolitan area. It is also true that in a number of cases single metropolitan districts of 1940 have been split into two standard metropolitan areas. Many metropolitan districts would have been changed, of course, had they been brought up to date for 1950.

In general, then, the two kinds of areas are not comparable. The fact that metropolitan districts were defined almost wholly in terms of density and that standard metropolitan areas include whole counties means that the population density of the standard metropolitan area is considerably lower on the average and shows more variation from one area to another. Differences between the two types of areas are relatively minor in New England and would have been even less had the metropolitan districts been brought up to date.

The urbanized area can be characterized as the physical city as distinguished from both the legal city and the metropolitan community. Urbanized areas are smaller than standard metropolitan areas and in most cases are contained in standard metropolitan areas. However, in a few instances, the fact that the boundaries of standard metropolitan areas are determined by county lines, and those of urbanized areas by the pattern of urban growth, means that there are small segments of urbanized areas which lie outside standard metropolitan areas. In general, then, urbanized areas represent the thickly settled core of the standard metropolitan areas, with the exceptions noted above. Because of discontinuities in land settlement, there are also some cases in which a single standard metropolitan area contains two urbanized areas. The lists of urbanized areas and of standard metropolitan areas also differ somewhat because the 1950 population of cities was not

Population of Standard Metropolitan Areas

and Their Component Parts, 1950

The aggregate population of the 168 standard metropolitan areas in continental United States in 1950 was 84,500,680, and their aggregate area was 207,583 square miles, or 7.0 percent and 56.1 percent of the total land area and total population, respectively. Of the population of 84,500,680, 49,412,792 persons, or 58.5 percent, were living in central cities, and the remaining 35,087,888 were in the areas outside central cities (tables 26 to 29). The 14 standard metropolitan areas with a population of a million or more in 1950 had an aggregate population of 44,440,496, or more than half of the total, whereas the total population of the 17 areas of fewer than 100,000 was 1,430,076. The New YorkNortheastern New Jersey Standard Metropolitan Area had the largest population (12,911,994), and the Laredo Standard Metropolitan Area, the smallest population (56,141). Somewhat more than two thirds of the 168 standard metropolitan areas were areas with total populations ranging between 100,000 and 500,000.

There were 40 standard metropolitan areas with less than half their total population in their central cities. These areas ranged from those such as the Los Angeles, Boston, Pittsburgh, and Atlanta areas, to relatively small ones such as the Orlando, Asheville, and Jackson, Mich., areas. These standard metropolitan areas lie in 19 States, largely in the Northeast and the South, but are most numerous in 2 States-Pennsylvania and California. Of the 12 standard metropolitan areas with principal central cities in Pennsylvania, 9 have more than half their population outside their central cities, and in California 6 out of 8 areas are of this class.

Trends in Population, 1940 to 1950

The population of 84.5 million in standard metropolitan areas represents an increase of 15.2 million, or 22.0 percent, over the 69.3 million inhabitants of those areas in 1940 (table 27). The rate of increase in the population of central cities during the decade, 13.9 percent, was slightly less than that for the country as a whole. In the outlying parts of standard metropolitan areas, however, the population increased by about 9.2 million, or 35.5 percent of the 1940 population of these areas. Standard metropolitan areas stand in marked contrast then with the remainder of the country in which the rate of increase was only 6.1 percent. Of the increase of about 19 million for the United States during the decade, about four-fifths occurred in standard metropolitan areas and nearly one-half occurred outside the central cities.

The population increased most rapidly in those standard metropolitan areas that ranged in size in 1950 from 500,000 to 1,000,000, where the rate of increase was 28.4 percent (table M). The rate of increase for standard metropolitan areas of 1,000,000 or more (19.0 percent) was the lowest. The figures for areas in the sizeclasses 100,000 to 250,000 and 250,000 to 500,000 indicate increases of about 24 percent, and the rate of growth in areas of less than 100,000 (22.5 percent) was about the same as that for all the areas.

Hazleton, Duluth-Superior, and Wheeling-Steubenville. In each of these areas except the Duluth-Superior area, the central cities also lost population. Of the 162 standard metropolitan areas that gained population, 91, or slightly more than half, had increases of 20 percent or more, and 46, or slightly more than a fourth of all standard metropolitan areas, had increases of one-third or more. One area, that of Albuquerque, more than doubled in population with an increase of 109.9 percent.

Population Density

In 1950, the population per square mile of land area for all of the 168 standard metropolitan areas was 407 as compared with 51 for the United States as a whole (table 29). There were three standard metropolitan areas-Milwaukee, New York-Northeastern New Jersey, and Boston-with more than 3,000 inhabitants per square mile. At the other end of the scale eight standard metropolitan areas-Amarillo, Fresno, San Angelo, Pueblo, Phoenix, Duluth-Superior, Laredo, and San Bernardino-had a population density of less than 50 per square mile. This extreme variation in density among standard metropolitan areas is an indication, of course, of the limitations of counties as a basis for defining such areas. The area of San Bernardino County, Calif., for example, is greater than that of any of the New England States except Maine, and it is more than 5 times as large as the New York-Northeastern New Jersey Standard Metropolitan Area and 84 times as large as the Milwaukee Standard Metropolitan Area. In short, in those parts of the country where counties are large the use of counties yields only a very rough approximation of genuinely metropolitan areas. There was also considerable variability, however, in density among the central cities of standard metropolitan areas. Among central cities the number of persons per square mile ranged from 1,304 in the Pittsfield Standard Metropolitan Area to 24,537 in the New YorkNortheastern New Jersey area. For areas outside of central cities, this figure ranged from 1 in the Laredo Standard Metropolitan Area to 2,172 in the Boston area.

Relationship Between Population in Standard Metropolitan Areas and Urbanized Areas

Table N presents a cross-classification of the population by residence inside and outside standard metropolitan areas and urbanized areas. Of the 84,500,680 persons living in standard metropolitan areas, 68,989,014, more than four-fifths, were also residents of urbanized areas. On the other hand, only 260,134 persons were living in urbanized areas but outside standard metropolitan areas. There were no standard metropolitan areas established for Muskegon, Mich., and Fort Smith, Ark. If the population of the urbanized areas established for these cities is excluded, the number of persons living in segments of the urbanized areas which extend beyond the boundaries of standard metropolitan areas was 118,843.

Standard Metropolitan Areas in Hawaii and Puerto Rico

In the Territories and possessions of the United States, there are

as great as half a million (table 27). The largest of the four areas was that of San Juan-Río Piedras, P. R., which had a population of 465,741, and was slightly smaller in population than the Memphis Standard. Metropolitan Area, which ranked thirty-sixth in size in continental United States.

The Honolulu Standard Metropolitan Area has a population of 353,020, slightly less than that of the Wheeling-Steubenville area, which ranked forty-eighth in size in continental United States. It is the only standard metropolitan area in the Territory of Hawaii and contains more than 70 percent of the population of the Territory. The other two standard metropolitan areas outside continental United States are the Ponce and Mayagüez areas in Puerto Rico, with 126,810 and 87,307 inhabitants, respectively 1940 METROPOLITAN DISTRICTS Definition

Metropolitan districts were defined for every city of 50,000 inhabitants or more in 1940, two or more such cities sometimes being in one district. In general, metropolitan districts included, in addition to the central city or cities, all adjacent and contiguous minor civil divisions or incorporated places having a population density of 150 or more per square mile. Since the metropolitan districts are being replaced by the standard metropolitan areas, no attempt was made to redefine the 1940 metropolitan districts or to define metropolitan districts for those cities which attained a population of 50,000 or more in 1950. Insofar as possible, the 1950 figures represent the population of the territory included in the metropolitan districts in 1940, as an effort was made to use in the enumeration the 1940 limits of the metropolitan districts even though the pertinent minor civil divisions might have changed their boundaries. For the constituent parts of the metropolitan districts in 1940, see reports of the Sixteenth Census (1940), Population, Vol. I.

Trends in Population, 1940 to 1950

The 1950 population of the 140 metropolitan districts of 1940 was 76,203,556, an increase of 13,237,783, or 21.0 percent, over the 1940 population. Almost one-fifth of this increase was contributed by the Los Angeles and New York-Northeastern New Jersey Metropolitan Districts. All but four of the districts gained. The rates of change ranged from a gain of 90.5 percent for Corpus Christi to a loss of 14.0 percent for Scranton-Wilkes-Barre. All but 1 of the 17 districts which gained more than 50 percent were located in the South and West and were heavily concentrated in California and Texas. An additional 24 districts gained more than a third but less than a half. None of the districts which gained more than a third were in the Northeast. Three of the four metropolitan districts which lost population were located in Pennsylvania.

STATE ECONOMIC AREAS AND ECONOMIC SUBREGIONS State Economic Areas

State economic areas are relatively homogeneous subdivisions of States. They consist of single counties or groups of counties which have similar economic and social characteristics. The boundaries of these areas have been drawn in such a way that each State is subdivided into relatively few parts, with each part having certain significant characteristics which distinguish it from adjoining areas. The country has been subdivided into 501 State economic areas. In publications from the Population Census, however, some of the thinly populated agricultural areas have been combined.

The grouping of the 3,103 counties or equivalent subdivisions of the United States into State economic areas is the product of a special study sponsored by the Bureau of the Census in cooperstion with the Bureau of Agricultural Economics and several State and private agencies. The delimitation procedure was