The U.S. Census through the decades: Images and facts from the last century
As the 2020 Census gets underway, take a look back at images and facts from the past century.
All images via the U.S. Census Bureau.
1870 Census

In 1870, over 6,500 marshals and assistants counted the U.S. population, which had grown to over 38 million. It wasn't until 1880 that specially trained enumerators carried out the census.
1904 Hollerith Tabulator

A Census Bureau employee uses a Hollerith Tabulator to tabulate results from the 1900 census. The results of the tabulation are displayed on dials and he is manually operating a "pantograph" with his left hand and a card reading press with his right hand. The pantograph punched holes in cards for tabulation. The press contained metal pins that passed through the punched cards holes completing an electrical circuit when each pin made contact with a well of mercury below each hole, tabulating the data each hole represented on the dials.
1920 Census

The 1920 Census was the first in which the majority of the U.S. population, including recent immigrants, lived in urban areas.
1930 Card Punching

A Census Bureau employee translates handwritten information on the census schedule to holes on a punch card using a "card puncher." The punch cards are then sorted and tabulated.
1930 Census Interview From Horseback

Enumerator interviewing by horseback for the 1930 census.
1940 Census Taker

Although the records collected by this 1940 census taker were confidential until their release in 2012, the National Archives, state libraries, and genealogical organizations have many other resources that are available to the public without restrictions.
1940 Sorting Farm and Ranch Punch Cards

A battery of mechanical sorters prepare punch cards containing data from the 1940 Farm and Ranch Census for tabulation. The Census Bureau began using punch cards to sort and tabulate census data following the 1890 census. The machinery used to handle the punch cards grew steadily faster until computers and magnetic computer tape replaced punch cards in the 1960s.
1950 Census

Only twenty questions were on the 1950 census form, which made it easier for this Virginia mother to respond to the enumerator's questions while at home with her young children.
1950 Microfiliming the 1900 Census Records

Census Bureau employees use Recordak Microfilming machines to photograph 76 million records from the 1900 census. The microfilmed records can easily be searched to supply citizens with proof of age documentation needed to obtain Social Security and retirement benefits and passports.
1960 Census

All urban residents in the U.S. received a combined population and housing questionnaire by mail for the first time in 1960. Residents completed the questionnaire themselves and kept it until an enumerator came to collect the form.
1960 FOSDIC Captures Responses

FOSDIC (Film Optical Sensing Device for Input to Computers). First developed in 1953 for the 1960 Census of Population and Housing. This equipment scans reels of micofilmed census questionnaires to capture responses which are transferred to magnetic tape readable by computers.
1970 Census

Enumerators in 1970 were only sent out to collect information from non-responding residents, as it was the first census to operate on a true mail-out mail-back system.
1980 Census Mail-Out Mail-Back System

The mail-out mail-back system worked well for the 1980 Census, which is considered one of the most accurate in modern times.
1980 Preparing "Master Address Registers"

Preparation of Master Address Registers.To conduct the 1980 field enumeration, Census Bureau enumerators used Master Address Registers, like those prepared by this Jeffersonville, IN Census Bureau employee, to identify their assigned housing units.
1990 Census

The 1990 Census did not fare as well as its predecessor. For the first time since 1940, there was an increase in the estimated net undercount. Also, the mail response rate dropped to 65 percent, the lowest since 1960.
1990 Census Enumeration in New Mexico on Horseback

An enumerator (right) conducts the 1990 census in New Mexico on horseback.
Census Taker visits resident during 2000 Census.jpg

Census 2000 reversed the decades-long decline in response rates. It was also the first to use a paid advertising campaign to motivate participation, and studies have shown it to be the most accurate census in recent decades.
2010 Census Event: Census in Schools, St. Louis

U.S. Census Bureau Director Robert Groves spoke to students at Gateway Math and Science Elementary School during the St. Louis launch of the 2010 Census in Schools program. Census in Schools was designed for students in kindergarten through 12th grade. The program reached 118,000 schools and 56 million students nationwide.