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Urban agglomerations are contiguous areas of continuously developed urban territories.
Urban agglomeration data have typically not been reported by the Census Bureau,
the rationale being that they become progressively meaningless the larger the urban agglomeration area becomes.
It remains that urban agglomerations are of interest. New information surfaces as the Census
Bureau revises definitions relating to the urban geography for Census 2010.
United States in Global Perspective
The United Nations reports global urban agglomergation data by country.
For 2009, Delhi, India at 36.5 million and Toyko, Japan at 21.7 million are reported as the largest.
The UN site reports the New York agglomeration at 19.3 million which is far below the 29.0 million shown in the table below.
At issue are the geographic boundaries for each area; there is no global standard definition for metros nor urban agglomeration areas.
Potential Agglomeration Areas & Census 2010
Based on Census 2000 Urbanized Areas (UAs), the
Census Bureau has identified 52 potential agglomerations consisting of
multiple and currently separate UAs. These agglomerations contain UAs that
currently are contiguous as well as some that are in close proximity to each other
and that potentially could form a continuous agglomeration when areas
are redefined based on 2010 Census data.
52 Potential Agglomeration Areas Table
A table presented below lists the potential agglomerations, the
component UAs, and the estimated population based on the 2006–2008
ACS 3-year estimates (3-year estimates were used because not all UAs
met the 65,000 person threshold for ACS 1-year estimates).
Los Angeles-Long Beach-Santa Ana, CA; Riverside-San Bernardino, CA;
Camarillo, CA; Hemet, CA; Oxnard, CA; Santa Barbara, CA; Santa
Clarita, CA; Simi Valley, CA; Temecula-Murrieta, CA; Thousand Oaks,
Chicago-Kenosha-Racine-Round Lake Beach
Chicago, IL-IN; Kenosha, WI; Round Lake Beach-McHenry-Grayslake, ILWI;
Denver-Aurora, CO; Boulder, CO; Longmont, CO; Lafayette-Louisville, CO
St. Louis, MO-IL; Alton, IL
Orlando, FL; Ocala, FL; Kissimmee, FL; Lady Lake, FL; Leesburg-Eustis,
Pittsburgh, PA; Uniontown-Connellsville, PA; Monessen, PA
Kansas City-Lee’s Summit
Kansas City, MO-KS; Lee’s Summit, MO
Salt Lake City-Ogden-Layton
Salt Lake City, UT; Ogden-Layton, UT
Indianapolis, IN; Anderson, IN
Charlotte, NC-SC; Gastonia, NC; Concord, NC; Rock Hill, SC
Nashville-Davidson, TN; Murfreesboro, TN
Raleigh, NC; Durham, NC
Palm Bay-Melbourne-Titusville-Vero Beach
Palm Bay-Melbourne, FL; Titusville, FL; Vero Beach-Sebastian, FL; Port
St. Lucie, FL
Oklahoma City, OK; Norman, OK
Honolulu-Kailua (Honolulu County)
Honolulu, HI; Kailua (Honolulu County), HI
McAllen, TX; Harlingen, TX
Greensboro, NC; High Point, NC; Winston-Salem, NC
Sarasota-Bradenton, FL; North Port-Punta Gorda, FL
Bonita Springs-Naples-Cape Coral
Bonita Springs-Naples, FL; Cape Coral, FL
Harrisburg, PA; York, PA; Lebanon, PA
, SC; Spartanburg, SC; Mauldin-Simpsonville, SC
Pensacola-Fort Walton Beach
Pensacola, FL-AL; Fort Walton Beach, FL
Stockton, CA; Lodi, CA; Manteca, CA
Spokane, WA-ID; Coeur d’Alene, ID
Boise City, ID; Nampa, ID
Modesto, CA; Turlock, CA
South Bend, IN-MI; Elkhart, IN-MI
Salinas, CA; Santa Cruz, CA; Watsonville, CA
Charleston, WV; Huntington, WV-KY-OH
Santa Rosa, CA; Petaluma, CA
Rockford, IL; Beloit, WI-IL
Atlantic City, NJ; Wildwood-North Wildwood-Cape May, NJ
Appleton, WI; Oshkosh, WI
Beaumont, TX; Port Arthur, TX
Macon, GA; Warner Robins, GA
Kingsport, TN–VA; Johnson City, TN
Fairfield, CA; Vacaville, CA
Census 2010 Agglomeration Designation
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The Census Bureau is considering applying a 1,000,000 person minimum population
threshold to identify agglomerations to be split, but seeks comment on the
appropriate population size threshold to determine which large agglomerations
would be split. Other minimum population thresholds under consideration are 500,000 and 250,000.
Based on 2006–2008 ACS estimates, 27 of the 52 potential agglomerations have
populations less than 1,000,000; 14 have populations less than 500,000; and four
have populations less than 250,000. If a threshold of 1,000,000 people is chosen
as the minimum for splitting large agglomerations, all formerly separate
UAs in agglomerations of less than 1,000,000 people would be merged to
form a single UA. If 500,000 people is adopted as the minimum threshold,
then all formerly separate UAs in agglomerations of less than that
threshold would be merged. Because UAs form the cores of metropolitan
statistical areas, the merger of formerly separate UAs might affect the
delineation of metropolitan and micropolitan statistical areas. It is
important to note that some of the agglomerations listed below are
contained within the same metropolitan statistical area, and as a result, would
not be split, regardless of the threshold chosen. The agglomerations are: Dallas-
Fort Worth; Houston-Texas City; Phoenix-Mesa; San Diego-Mission Viejo;
St. Louis-Alton; Pittsburgh-Uniontown-Monessen; Kansas City-Lee’s Summit;
Charlotte-Gastonia-Concord; Nashville-Murfreesboro; Oklahoma City-Norman;
Honolulu-Kailua; Stockton-Lodi-Manteca; Boise City-Nampa; Modesto-
Turlock; Santa Rosa-Petaluma; Beaumont-Port Arthur; and Fairfield-
Census 2000 Urban Area Criteria & Proposed Census 2010 Criteria
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Differences Between Census 2000 Urban Area Criteria
& Proposed Urban Area Criteria for the 2010 Census
Census 2000 Criteria
Proposed 2010 Census Criteria
Analysis units for delineation of initial urban area cores
Block groups of less than 2 square miles in area and population density of at least 1,000 persons per square mile
Census tracts of less than 3 square miles in area and population density of at least 1,000 persons per square mile
Jumps - maximum distance (measured along a road feature)
Use of Land Use/Land Cover Data
Nationwide land use/land cover data sets were not available.
Use of National Land Cover Database (NLCD) to identify 1) territory with a high degree of impervious surface land cover as an indicator of non-residential urban land uses that should be considered for inclusion in an urban area; and 2) land cover that restricts development; e.g., marshes, wetlands, water.
Qualification of airports (when adjacent to other qualifying territory)
10,000 or more enplanements (departing passengers) annually.
2,500 or more enplanements annually.
Identification of central places
Central places identified based on population size.
Central places not identified.
Minimum population residing outside institutional group quarters
As a result, 24 urban clusters were defined consisting entirely or predominantly of population residing in institutional group quarters.
At least 1,500 persons must reside outside institutional group quarters for the area to qualify as an urban area.
Splitting Large Agglomerations
The agglomeration has at least 50,000 people in each of at least two different metropolitan statistical areas (MSAs) or primary metropolitan statistical areas (PMSAs), and the distance across the narrowest corridor of qualifying territory is less than 3 miles. The split will occur at a location near the MSA or PMSA boundary at which the width of the corridor is less than 3 miles.
The agglomeration has at least 50,000 people in each of at least two different consolidated metropolitan statistical areas (CMSAs), and the distance across the narrowest corridor of qualifying territory is less than 3 miles. The split will occur at the CMSA boundary.
The agglomeration encompasses at least 1,000,000 people. The split will occur at the metropolitan statistical area boundary (or metropolitan New England city and town area in New England). If an incorporated place or census designated place crosses the metropolitan statistical area boundary, the split occurs along the place boundary. The place is assigned to the resulting UA that contains the largest proportion of the place's land area.
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