• Ongoing → American Community Survey
• Autumn 2019 → In-field Address Canvassing began in August and ended in October
• January 2020 → Census Bureau's advertising campaign began
• January 21, 2020 → Enumeration of Remote Alaska began in Toksook Bay
• March 12, 2020 → Response online at 2020census.gov and by telephone began
• April 1, 2020 → 2020 Census Day
• August 11, 2020 → In-person follow-up began for households that did not submit a Census form
• October 15, 2020 → Last day to participate in the 2020 Census

The 2020 questionnaire asked respondents for basic demographic information, such as birth date, sex, and race. It didn't ask for information about income, health, religion, citizenship, or voting history.

The Census Bureau not only counts everyone living in the U.S. on Census Day, it must also tie each person to the spot on the ground where he or she lives. This necessity drives Type of Enumeration Areas (TEA) delineation decisions.

Self-Response
In 2020, the Census Bureau contacted most households by mail. The Postal Services delivers mail to households in Self-Response areas, which included about 180,000 Alaska households in places such as Anchorage, Fairbanks, and Juneau. When a housing unit in these areas did not respond, census workers followed up with additional mail or as many as six in-person visits.

Update Leave
People living in medium-sized settlements without mail delivery, such as Valdez, Bethel, and Nome, received hand-delivered census materials at their home. These areas were called Update Leave areas; “update” means census employees verified, corrected, or added geographic coordinates of housing units as they delivered materials. In 2010, about 60,000 Alaska households were counted this way. When the Census Bureau did not receive a response from a housing unit in an Update Leave area, employees followed up in person as many as six times.

Remote Alaska
People living in the most remote places in the country, including much of Alaska, were counted in person. As with Update Leave areas, these places do not have at-home mail delivery.

In Remote Alaska areas, enumerators verified the location of each housing unit, knocked on doors to conduct interviews about the number of people who lived there April 1, and got their work validated by a sworn-in local official. This process allowed village leaders to review and certify the count for accuracy. These areas had about 30,000 housing units in 2010.

Update Enumerate
Update Enumerate areas were counted in a similar way to Remote Alaska areas, except no village leader validated the count. When no one answers the door at these housing units, the enumerator does not follow up a second time and may seek information about the household from a neighbor or other proxy. In 2010, the Census Bureau used this method for about 4,000 households in sparsely populated areas of Southeast Alaska.

Households in any TEA may also have been reinterviewed, because a sample of households are double-checked as a quality-control measure.

View the Census Bureau's map of TEAs for the 2020 Census here.

The U.S. Census Bureau uses residence criteria to determine where people are counted during each decennial census, in accordance with the concept of “usual residence,” or where a person lives and sleeps most of the time. This is not always the same as their residence for tax purposes, voting residence, or preference. In a nutshell, the residence criteria say:

1. Count people at their usual residence, which is where they live and sleep most of the time.
2. People in certain types of group facilities on Census Day were counted at the group facility.
3. People who do not have a usual residence, or who cannot determine a usual residence, were counted where they are on Census Day.

Determining usual residence is straightforward for most people. However, some living arrangements are less straightforward, such as homelessness, seasonal or second residences, hospitals, shared custody arrangements, college, military, and worker dormitories.

The 2020 criteria were basically unchanged from 2010, but the way they are applied changed for five residence situations.

• Overseas military and civilian employees of the U.S. government
  The 2020 Census counted military and civilian federal employees who were temporarily deployed overseas on Census Day at their usual home address in the United States, as part of the resident population, instead of at their home state of record. Military and civilian employees who were stationed or assigned overseas on Census Day, as well as dependents living with them overseas, were counted in their home state of record for apportionment purposes only.
• Overseas federal employees who were not U.S. citizens
  The 2020 Census counted noncitizens who were military or civilian federal employees deployed, stationed, or assigned overseas on Census Day in the same way as U.S. citizens who are included in the federally affiliated overseas count.
• Maritime/Merchant Vessel Crews
  The 2020 Census counted crews of U.S. flag maritime or merchant vessels who were sailing between a U.S. port and a foreign port on Census Day at their usual home address, or at the U.S. port if they have no usual home address.
• Juveniles in Treatment Centers
  The 2020 Census counted juveniles staying in non-correctional residential treatment centers on Census Day at their usual home address, or at the facility if they have no usual home address.
• Religious Group Quarters Residents
  The 2020 Census counted people living in religious group quarters on Census Day at the facility.

For more information about the specific criteria and situations, please see Federal Register Rule 83 FR 5525. Census Bureau Memorandum 2018.04 also contains relevant information.

Local Update of Census Addresses (LUCA) is an opportunity for designees within local governments to review the Census Bureau’s confidential list of residential housing units within their jurisdiction before each decennial census. Participants may provide additions, corrections, deletions, structure point coordinates, and road updates to that list. In order to count everyone in the right place, the Census Bureau relies on a complete and accurate list of housing units in order to reach every place people are living. Local government participation in LUCA can help ensure an accurate count.

People living in on-base barracks and dormitories were counted through a method called "facility self-enumeration" for group quarters. This means a census worker trained a point-of-contact for each military installation to distribute census questionnaires, collect them when complete, and return them to the census worker at an agreed-upon time.

People living in on-base housing units were counted via Self-Response, Update/Leave, or Remote Alaska enumeration, depending on location. For details by area, see the Census Bureau's Type of Enumeration Area map.

Contrary to the Census Bureau’s plan described in its 2020 Census Detailed Operational Plan for Group Quarters Operation, released Sept. 29, 2017, the Census Bureau did not use administrative records supplied by the Defense Manpower Data Center to enumerate on-base military barracks, dormitories, and housing units.

Updated Aug. 22, 2019

The purpose of address canvassing is (1) to develop a complete and accurate address list and spatial database for enumeration and tabulation, and (2) to determine the type and address characteristics for each living quarter.

For the 2010 Census, address canvassing field staff ("listers") traversed almost every block in the nation to compare what they observed on the ground to the Census Bureau's address list. Listers verified or corrected current addresses, added new addresses, and deleted addresses that no longer existed. Listers also collected GPS coordinates for each structure and added new streets to the list.

For the 2020 Census, the bureau used new in-office canvassing methods and reduced in-field canvassing. In-office address canvassing used geographic evidence, such as imagery and comparisons of the Census Bureau's address list to partner-provided address lists, to assess and update the bureau's address list.

In-office address canvassing started with an imagery-based review to assess the extent to which the number of addresses on the bureau's address list was consistent with the number of addresses visible in recent satellite imagery. Changes between recent imagery and older imagery were also be assessed.

Areas identified as ones of growth, decline, undercoverage of addresses, or overcoverage of addresses during the review process were further researched using other data sources, including online GIS viewers, parcel data, files acquired through ongoing geographic partnership programs, and commercial data. These other data sources were used in office to resolve discrepancies, where possible. Areas that weren't able to be resolved in office became the universe of geographic areas to be worked during in-field address canvassing.

The Census Bureau predicted 35 percent of addresses in self-response areas would require in-field work.

In-field address canvassing is the process in which listers visit specific geographic areas to identify every place where people could live or stay, and then to compare what they see on the ground to the bureau's existing address list and either verify or correct the address and location information. For the 2020 Census, listers also classified each living quarters as either a housing unit or a group quarters facility. Listers knocked on doors at every structure in an attempt to locate living quarters. If someone answered, the lister asked if there are any additional living quarters in the structure or on the property. If no one answered, the lister updated the address list as best he or she could by observation.

For more information, including a map of areas selected for in-field address canvassing, visit the Census Bureau's press kit about the operation.

The 2017 Census Test was an opportunity for the Census Bureau to test the feasibility of collecting tribal enrollment information from respondents. Areas with relatively high concentrations of people who identify as American Indian or Alaska Native, including Alaska, were oversampled in the test. However, only households with mailable city-style addresses were included in the sample.

The test was conducted in spring 2017.

Based on feedback the Census Bureau received, the bureau decided not to add a question about tribal enrollment to the 2020 Census questionnaire.

The images below show the content of the 2017 Census Test questionnaire.

Complete Count Committees (CCCs) can form at any time.

CCCs are volunteer committees that increase awareness of the decennial census and motivate residents to respond. Committee members represent a cross section of each community, including government agencies; tribes; education, business, nonprofit, and faith-based organizations; and the media. Using local knowledge, CCCs plan and implement census awareness campaigns that address the special characteristics of their communities. Local campaigns are designed to reach traditionally undercounted populations by stressing the importance of an accurate census count, including how data are collected and used.

Nationwide, 11,800 CCCs formed for the 2000 Census, the majority of which were local government committees.

Since the 1980 Census, CCCs have played a major role in raising awareness of each decennial census. CCCs nationwide implement key activities, including:

• Holding events, such as a Census Day "Be Counted" parades, that generate interest and participation.
• Distributing census information and materials through websites, newsletters, and at events.
• Partnering with organizations in their communities to include census promotion in their communications.

The Census Bureau aims to count everyone living in the U.S., including people experiencing homelessness. People are counted wherever they live on Census Day or where they are staying on Census Day if they have no permanent place to live. The bureau counts people at shelters, soup kitchens, and outdoor encampments through two operations: Service-Based Enumeration and Enumeration at Transitory Locations. However, there is no one definition of homelessness, and the decennial census questionnaire does not ask people if they are experiencing homelessness. After the decennial census, the Census Bureau publishes a count of people staying at emergency and transitional shelters on Census Day but not a count of people experiencing homelessness.

The Census Bureau worked with state, local, and tribal governments to get locations for soup kitchens, emergency shelters, outdoor encampments, and other places people may have been staying on Census Day.

Results from the 2010 Census can be found online:

• data.census.gov table: Group Quarters Population by Group Quarters Type
• Special Report: The Emergency and Transitional Shelter Population: 2010

By law, all information that the Census Bureau collects about individuals is confidential. This includes responses on census questionnaires, names, addresses, and residential locations. After 72 years, personally identifiable information collected for a decennial census is released to the public.

For more information, visit the Census Bureau's website.

The primary use of decennial census counts is the apportionment of seats allocated to the states for the House of Representatives. This requirement is mandated by the U.S. Constitution.

Decennial census data at the census block level are used by governmental entities for redistricting.

The Census Bureau also uses decennial census results to determine the statistical sampling frames for the American Community Survey (ACS), which replaced the long form in the decennial census, and dozens of other surveys conducted by the Census Bureau. The results of these surveys are used to support important government functions, such as appropriating federal funds to states and local communities (an estimated $675 billion annually); producing monthly unemployment, housing vacancy, and poverty rates; and publishing health and education data.

Finally, decennial data play an increasingly important role in U.S. commerce and the economy. As people expand their use of data to make decisions at the local and national levels, they increasingly depend on data from the Census Bureau to make these decisions.