[Federal Register Volume 62, Number 85 (Friday, May 2, 1997)]
[Notices]
[Pages 24077-24080]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-11453]


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DEPARTMENT OF COMMERCE

Bureau of the Census
[Docket No. 970408082-7082-01]
RIN 0607-XX28


Block Group Program for Census 2000--Proposed Criteria

AGENCY: Bureau of the Census, Commerce.

ACTION: Notice of proposed program revisions and request for comments.

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SUMMARY: Block groups are geographic statistical divisions of census 
tracts, each of which consists of from one to nine block groups. A 
block group comprises a reasonably compact and contiguous cluster of 
census blocks. The primary goal of the block group program is to 
provide data users with a geographic subunit of census tracts for which 
decennial census sample and 100 percent data are tabulated and 
disseminated.
    The Census Bureau first used block groups in its data presentations 
from the 1970 census. It did this in lieu of providing data summaries 
for enumeration districts in areas that had census block numbers. As 
census blocks and block groups became increasingly popular with data 
users, the Census Bureau established them in many new areas. By 1990, 
there was complete census block and block group coverage for all of the 
United States, Puerto Rico, and the Island Areas (American Samoa, Guam, 
the Northern Mariana Islands, and the Virgin Islands of the United 
States).
    Through the 1990 census, block groups were subunits either of 
census tracts or of similar entities known as block numbering areas 
(BNAs). For areas where census tracts did not exist, the Census Bureau 
had established BNAs to control the numbering of census blocks within 
block groups. A county or statistically equivalent entity 1 
could, therefore, have either census tracts or BNAs. For Census 2000, 
the Census Bureau will merge the two programs and convert all BNAs to 
census tracts.
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    \1\ Includes parishes in Louisiana; boroughs and census areas in 
Alaska; independent cities in Maryland, Missouri, Nevada, and 
Virginia; that portion of Yellowstone National Park in Montana; 
districts in American Samoa and the Virgin Islands of the United 
States; municipalities in the Northern Mariana Islands; municipios 
in Puerto Rico; and the entire areas constituting the District of 
Columbia and Guam. This notice will refer to all these entities 
collectively as ``counties.''
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    To determine boundaries and identification numbers for block 
groups, the Census Bureau offers a program to local participants, such 
as locally identified agencies and American Indian tribal officials, 
whereby they can review and update the boundaries of the block groups 
delineated for the 1990 census and suggest revisions according to the 
criteria developed and promulgated by the Census Bureau. The Census 
Bureau then reviews the resulting block groups for conformance to these 
criteria.
    As the first step in this process, the Census Bureau is requesting 
comments on the criteria proposed for the delineation of block groups 
in conjunction with Census 2000. These criteria will apply to the 50 
states, American Indian and Alaska Native areas, Puerto Rico, and the 
Island Areas. The Census Bureau may modify and, if

[[Page 24078]]

necessary, reject proposals for block groups that do not meet the 
criteria established following this notice.
    Besides the proposed criteria, this notice includes a description 
of the changes from the criteria used for the 1990 census and a list of 
definitions of key terms used in the criteria.

DATES: Any suggestions or recommendations concerning the proposed 
criteria should be submitted in writing by June 2, 1997.

ADDRESSES: Director, Bureau of the Census, Washington, DC 20233-0001.

FOR FURTHER INFORMATION CONTACT: Dr. Joel Morrison, Chief, Geography 
Division, Bureau of the Census, Washington, DC 20233-7400, telephone 
(301) 457-1132, or e-mail ([email protected]).

SUPPLEMENTARY INFORMATION: The block group delineation criteria have 
evolved in response to decennial census practices and the preferences 
of program participants and data users. After each decennial census, 
the Census Bureau, in consultation with participants and data users, 
reviews and revises these criteria. Then, before the next decennial 
census, the Census Bureau offers state, tribal, and local officials an 
opportunity to correct, update, and otherwise improve the block group 
delineations.
    In July and August 1995, the Census Bureau issued invitations to 
local and tribal groups and agencies to participate in the delineation 
of statistical geographic areas for Census 2000. These included 
regional planning agencies, councils of governments, county planning 
agencies, officials of Federally recognized American Indian tribes, and 
officials of the 12 nonprofit Alaska Native Regional Corporations.
    During 1997, the Census Bureau will provide materials and detailed 
guidelines to program participants for the review and delineation of 
block groups for Census 2000.

A. Criteria For Delineating Block Groups For Census 2000

    The Census Bureau proposes the following criteria for use in 
delineating Census 2000 block groups.

1. General Characteristics

     A block group must meet the population and boundary 
feature criteria and comprise a compact piece of territory.
     A census tract boundary always must be a block group 
boundary.
     Each census tract must contain a minimum of one block 
group and may have a maximum of nine block groups.
     Block groups must cover the entire land and inland water 
area of a census tract.
     A block group entirely within an American Indian 
reservation (AIR) may extend across a state or county boundary for 
tabulations in the American Indian geographic hierarchy. For standard 
data tabulations, the portion of the block group in each state and 
county is treated as a separate block group.

2. Identification

     A block group consists of all blocks within a census tract 
that have the same first digit and is identified using that same first 
digit. For example in 1990, block group 3 included all census blocks 
numbered in the 300s. For Census 2000, the Census Bureau will introduce 
a four-digit block numbering system, and block group 3 will include all 
census blocks numbered in the 3000s within a census tract.
     The range of acceptable block group numbers is 1 through 
9. Block group numbers must always be unique within a census tract; 
that is, the same number cannot be repeated.
     The Census Bureau will assign a single ``zero'' block 
group to census tracts numbered ``0000.'' (In counties that have 
coastal water, territorial sea, or Great Lakes waters, the Census 
Bureau recommends establishing a ``0000'' census tract to provide 
complete area coverage.)

3. Boundary Features

    The Census Bureau recommends that block group boundaries follow 
visible and identifiable features; that is, visible, perennial natural 
and cultural features such as roads, rivers, canals, railroads, above-
ground high-tension power lines, and so forth. This provision makes the 
location of boundaries less ambiguous and easier for data users to 
locate.
    State and county boundaries are always block group boundaries. The 
Census Bureau also permits the use of other types of legal boundaries 
in some states and situations where the boundaries of these 
governmental units tend to remain unchanged between censuses. The 
following features are acceptable as block group boundaries:
     All minor civil division (MCD) boundaries (generally towns 
or townships) in Connecticut, Indiana, Maine, Massachusetts, New 
Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and 
Vermont.
     Those MCD boundaries not conjoint with the boundaries of 
incorporated places that themselves are MCDs (being either coextensive 
with or independent of MCDs) in Illinois (townships only, not election 
precincts), Iowa, Kansas, Michigan, Minnesota, Missouri (governmental 
townships only), Nebraska (townships only, not election precincts), 
North Dakota, Ohio, South Dakota, and Wisconsin.
     Barrio, barrio-pueblo, and subbarrio boundaries in Puerto 
Rico, census subdistrict boundaries in the Virgin Islands of the United 
States, MCD-county and island boundaries in American Samoa, and 
municipal district boundaries in the Northern Mariana Islands.
     All incorporated place boundaries in Connecticut, Maine, 
Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode 
Island, and Vermont.
     Conjoint incorporated place boundaries in other states; 
that is, the boundary separating two different incorporated places.
     AIR boundaries.
     American Indian trust land, Alaska Native village 
statistical area, and Alaska Native Regional Corporation boundaries, at 
the discretion of the Census Bureau, insofar as such boundaries are 
unambiguous for allocating living quarters as part of census 
activities.
    When the above types of features are not available for selection, 
the Census Bureau may, at its discretion, approve other nonstandard 
visible features, such as ridge lines, pipelines, intermittent streams, 
fence lines, and so forth. The Census Bureau also may accept, on a 
case-by-case basis, the boundaries of selected nonstandard and 
potentially nonvisible features, such as the boundaries of national 
parks and forests, cemeteries, or other special land-use properties, 
the straight-line extensions of visible features, and other lines of 
sight.

4. Population Thresholds

    The Census Bureau proposes standard size criteria for most block 
groups in the United States, Puerto Rico, and the Island Areas (see 
Table 1). Smaller optimum and minimum sizes are permissible for block 
groups located on AIRs or comprising special places. (Special places 
are correctional institutions, military installations, college 
campuses, workers' dormitories, hospitals, nursing homes, and group 
homes.)

[[Page 24079]]



                          Table 1.--Population Thresholds for Census 2000 Block Groups                          
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                                 Area(s)                                     Optimum      Minimum      Maximum  
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Standard (most areas)....................................................        1,500          600        3,000
AIRs.....................................................................        1,000          300        3,000
Special place block group................................................         none          300         none
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    If a block group located on an AIR crosses a county boundary or a 
state boundary, the minimum population size criterion applies to the 
entire area of the block group, not to the individual portions that are 
in separate counties or states.

5. Final Approval of Block Groups

    The Census Bureau reserves the right to approve all block group 
proposals for Census 2000. The Census Bureau will make an effort to 
reach agreement with local and tribal participants in the block group 
program, but cannot approve the use of block groups as submitted if 
they do not meet Census 2000 criteria. If necessary, the Census Bureau 
will revise block group boundaries where they do not meet the boundary 
and population size requirements.

B. Changes to the Criteria for Census 2000

    Most provisions of the block group criteria remain unchanged from 
those used in conjunction with the 1990 census, with the few exceptions 
summarized below:
    1. For 1990 and previous decennial censuses, the Census Bureau 
delineated the block groups in BNAs on the basis of the number of 
housing units rather than population. For Census 2000, the Census 
Bureau is merging the census tract and BNA programs to create a single 
census tract program, and the size criteria for all block groups will 
be on the basis of population rather than the number of housing units.
    2. For Census 2000, the Census Bureau is increasing the number of 
governmental units that have boundaries acceptable to use as block 
group boundaries. The added areas are: All MCDs in Indiana and selected 
MCDs in Illinois, Iowa, Kansas, Michigan, Minnesota, Missouri, 
Nebraska, North Dakota, South Dakota, and Wisconsin; the MCD-county and 
island areas of American Samoa; and villages in New York.
    3. The Census Bureau now allows officials of Federally recognized 
AIRs to establish block groups that cross state or county boundaries. 
While the Census Bureau will publish data for each state-county-census 
tract-block group part, it also plans to provide summed data for all 
block groups that are located within an AIR and that cross state or 
county boundaries.

Definitions of Key Terms

    Alaska Native Regional Corporation (ANRC)--A corporate entity 
established under the Alaska Native Claims Settlement Act of 1972, Pub. 
L. 92-203, as amended by Pub. L. 92-204, to conduct both the business 
and nonprofit affairs of Alaska Natives. Twelve ANRCs cover the entire 
State of Alaska except for the Annette Islands Reserve.
    Alaska Native village statistical area (ANVSA)--A statistical 
entity containing the densely settled extent of an Alaska Native 
village that constitutes an association, band, clan, community, group, 
tribe, or village recognized pursuant to the Alaska Native Claims 
Settlement Act of 1972, Pub. L. 92-203, as amended by Pub. L. 92-204.
    American Indian reservation (AIR)--A Federally recognized American 
Indian entity with boundaries established by treaty, statute, and/or 
executive or court order and over which American Indians have 
governmental jurisdiction. Along with reservation, designations such as 
colonies, communities, pueblos, rancherias, and reserves apply to AIRs.
    Block numbering area (BNA)--A small-area, statistical geographic 
division of a county or statistically equivalent area delineated in 
1990 instead of and generally geographically equivalent to a census 
tract. For Census 2000, the Census Bureau is merging the BNA program 
with the census tract program and converting all BNAs to census tracts.
    Census block--The smallest geographic entity for which the Census 
Bureau collects and tabulates decennial census information; bounded on 
all sides by visible and nonvisible features identified by the Census 
Bureau in computer files and on maps.
    Census tract--A small, relatively permanent statistical geographic 
subdivision of a county or statistically equivalent area defined for 
the tabulation of data. For Census 2000, the Census Bureau is replacing 
BNAs with census tracts.
    Coastal water--Water bodies between territorial seas and inland 
water, the encompassing headlands being greater than one mile apart and 
less than 24 miles apart.
    Conjoint--A description of a boundary shared by two adjacent 
geographic areas.
    Contiguous--A description of geographic areas that are adjacent to 
one another, sharing either a common boundary or point.
    Great Lakes waters--Water area beyond one-mile-wide headland 
embayments located in any of the five Great Lakes: Erie, Huron, 
Michigan, Ontario, or Superior.
    Incorporated place--A type of governmental unit, sanctioned by 
state law as a city, town (except in New England, New York, and 
Wisconsin), village, or borough (except in Alaska and New York), having 
legally prescribed limits, powers, and functions.
    Inland water--Water bodies entirely surrounded by land or at the 
point where their opening to coastal waters, territorial seas, or the 
Great Lakes is less than one mile across.
    Minor civil division (MCD)--The primary governmental or 
administrative division of a county in 28 states, Puerto Rico, and the 
Island Areas having legal boundaries, names, and descriptions. MCDs 
represent many different types of legal entities with a wide variety of 
characteristics, powers, and functions depending on the state and type 
of MCD. In some states, some or all of the incorporated places also 
constitute MCDs.
    Nonvisible feature--A map feature that is not visible on the 
ground, such as a city or county boundary through space, a property 
line, a short line-of-sight extension of a road, or a point-to-point 
line of sight.
    Special place--A specific location requiring special enumeration 
procedures because the location includes people not in households or 
the area includes special land use. Special places include facilities 
with resident population, such as correctional institutions, military 
installations, college campuses, workers' dormitories, hospitals, 
nursing homes and group homes and land-use areas such as national 
parks. A special place includes the entire facility, including 
nonresidential areas and staff

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housing units, as well as all group quarters population.
    Territorial seas--Water bodies not included under the rules for 
inland water, coastal water, or Great Lakes waters (see above).
    Visible feature--A map feature that one can see on the ground such 
as a road, railroad track, above-ground transmission line, stream, 
shoreline, fence, sharply defined mountain ridge, or cliff. A 
nonstandard visible feature is a feature that may not be clearly 
defined on the ground (such as a ridge), may be seasonal (such as an 
intermittent stream), or may be relatively impermanent (such as a 
fence). The Census Bureau generally requests verification that 
nonstandard features pose no problem in their location during field 
work.

    Dated: April 1, 1997.
Martha Farnsworth Riche,
Director, Bureau of the Census.
[FR Doc. 97-11453 Filed 5-1-97; 8:45 am]
BILLING CODE 3510-07-P