The data on place of work were derived from answers to long-form questionnaire Item 22, which was asked of a sample of the population 15 years old and over. This question was asked of people who indicated in question 21 that they worked at some time during the reference week. (For more information, see "Reference Week.")

Data were tabulated for workers 16 years old and over; that is, members of the armed forces and civilians who were at work during the reference week. Data on place of work refer to the geographic location at which workers carried out their occupational activities during the reference week. The exact address (number and street name) of the place of work was asked, as well as the place (city, town, or post office); whether or not the place of work was inside or outside the limits of that city or town; and the county, state or foreign country, and ZIP Code. If the persons employer operated in more than one location, the exact address of the location or branch where the respondent worked was requested. When the number and street name were unknown, a description of the location, such as the building name or nearest street or intersection, was to be entered.

In areas where the workplace address was coded to the block level, people were tabulated as working inside or outside a specific place based on the location of that address, regardless of the response to Question 22c concerning city/town limits. In areas where it was impossible to code the workplace address to the block level, people were tabulated as working in a place if a place name was reported in Question 22b and the response to Question 22c was either "yes" or the item was left blank. In selected areas, census designated places (CDPs) may appear in the tabulations as places of work. The accuracy of place-of-work data for CDPs may be affected by the extent to which their census names were familiar to respondents, and by coding problems caused by similarities between the CDP name and the names of other geographic jurisdictions in the same vicinity.

Place-of-work data are given for minor civil divisions (MCDs) (generally, cities, towns, and townships) in 12 selected states (Connecticut, Maine, Massachusetts, Michigan, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, and Wisconsin), based on the responses to the place-of-work question. The MCDs in these 12 states also serve as general-purpose local governments that generally can perform the same governmental functions as incorporated places. The U.S. Census Bureau presents data for the MCDs in all data products in which it provides data for places. Many towns and townships are regarded locally as equivalent to a place, and therefore, were reported as the place of work. When a respondent reported a locality or incorporated place that formed a part of a township or town, the coding and tabulating procedure was designed to include the response in the total for the township or town.

States are the primary governmental divisions of the United States. The District of Columbia is treated as a statistical equivalent of a state for data presentation purposes. For Census 2000, the U.S. Census Bureau also treats a number of entities that are not legal divisions of the United States as statistically equivalent to a state: American Samoa, the Commonwealth of the Northern Mariana Islands, Guam, Puerto Rico, and the Virgin Islands of the United States.

Each state and statistically equivalent entity is assigned a two-digit numeric Federal Information Processing Standards (FIPS) code in alphabetical order by state name, followed in alphabetical order by Puerto Rico and the Island Areas. Each state and statistically equivalent entity also is assigned a two-letter FIPS/U.S. Postal Service code and a two-digit census code. The census code is assigned on the basis of the geographic sequence of each state within each census division; the first digit of the code identifies the respective division, except for Puerto Rico and the Island Areas, which are not assigned to any region or division. The census regions, census divisions, and their component states are listed in Figure A-3.

The primary legal divisions of most states are termed "counties." In Louisiana, these divisions are known as parishes. In Alaska, which has no counties, the statistically equivalent entities are census areas, city and boroughs (as in Juneau City and Borough), a municipality (Anchorage), and organized boroughs. Census areas are delineated cooperatively for data presentation purposes by the state of Alaska and the U.S. Census Bureau. In four states (Maryland, Missouri, Nevada, and Virginia), there are one or more incorporated places that are independent of any county organization and thus constitute primary divisions of their states; these incorporated places are known as "independent cities" and are treated as equivalent to counties for data presentation purposes. (In some data presentations, they may be treated as county subdivisions and places.) The District of Columbia has no primary divisions, and the entire area is considered equivalent to a county for data presentation purposes. In American Samoa, the primary divisions are districts and islands; in the Northern Mariana Islands, municipalities; in the Virgin Islands of the United States, the principal islands of St. Croix, St. John, and St. Thomas. Guam has no primary divisions, and the entire area is considered equivalent to a county for data presentation purposes.

Each county and statistically equivalent entity is assigned a three-digit Federal Information Processing Standards code that is unique within state. These codes are assigned in alphabetical order of county or county equivalent within state, except for the independent cities, which are assigned codes higher than and following the listing of counties.