Enumeration Districts and Census Tracts

by | 30 Mar 2023

A census enumeration district (ED) is a defined geographic area representing a specific portion of a city or county. As defined by the U.S. Census Bureau, the coverage area of an enumeration district is the area for which a single enumerator (census taker) could complete a count of the population within the allotted time for that particular census year. For this reason, enumeration districts are redrawn for each decennial census to adjust for population shifts. The size of an ED can range from a few city blocks to an entire county in sparsely populated rural areas. In areas packed with high-rise apartment buildings, an enumeration district may be as small as a single block or portion thereof.

Numbers designate the enumeration districts for each census. For more recently released censuses, such as 1930–1950, enumerator districts are defined by two numbers joined with a hyphen. The prefix typically represents the county and the suffix a smaller ED area within the county. Large cities may use a unique prefix in place of the county prefix.

In 1950, baseball great Jackie Robinson, his wife, Rachel, and their two oldest children, were living in a home in the Addisleigh Park section of South Jamaica, Queens. Their 1950 Enumeration District (ED) was 41-2028, with 41 representing the borough of Queens, and 2028 designating the individual ED within the city bounded by Sayres Ave., 177th, Linden Blvd., and Marne Pl.

What Is an Enumerator?

Enumerators (census takers) are temporary employees of the U.S. Census Bureau, hired and trained to collect information from individuals and households in their assigned enumeration district for a particular census. For the 1950 Census enumeration, for example, each enumerator had either two weeks in urban areas or 30 days in rural areas to obtain information from each individual within their enumeration district. However, while the census was conducted over weeks, the data collected referred to a specific fixed date—the official census day. 

Using Enumeration Districts for Genealogy

With the ready availability of fully-searchable online census records, Enumeration Districts aren’t as crucial to finding people as they once were. They can still be helpful, however, in certain situations. When you can’t locate an individual in the index, or you’re dealing with a newly-released census that hasn’t yet been fully indexed, try browsing page-by-page through the records of the ED where you expect your relatives to be living. Enumeration District maps are also helpful for determining which path an enumerator may have followed through his particular district, helping us visualize the neighborhood and identify neighbors.

How to Locate an Enumeration District

To identify an individual’s enumeration district, we need to know where they lived when the census was taken, including the state, city, and street name. The street number is also crucial for long streets in larger cities. With this information, the following tools can help to locate the Enumeration District for each census:

  • Stephen P. Morse’s One-Step Tools website includes ED Finder tools for the 1880, 1900, 1910, 1920, 1930, 1940, and 1950 U.S. federal censuses.
  • Morse’s One-Step site also offers an ED conversion tool for converting between 1920 and 1930 and 1930 and 1940 Censuses.
  • The National Archives has online ED maps and geographic descriptions for the 1940 census and 1950 census. Descriptions of Census Enumeration Districts 1830–1890 and 1910–1950 can be found on the 156 rolls of NARA microfilm publication T1224, most of which are available digitally on FamilySearch. Enumeration District maps for 1900–1940 are available on the 73 rolls of NARA microfilm publication A3378, also available digitally on FamilySearch.

Census Tracts

In 1906, Dr. Walter Laidlaw, director of the Population Research Bureau of the New York Federation of Churches, proposed the idea of delineating permanent, small geographic areas that would retain their boundary from census to census to facilitate data analysis. The idea came about when, in 1905, the state of New York changed the boundaries of its assembly districts to adjust for population changes—a move that undermined the usefulness of Laidlaw’s neighborhood research based on the 1900 census assembly districts.

Before the 1910 census, Dr. Laidlaw divided New York City into 40-acre tracts called “districts” and persuaded the Census Office to extend the concept to seven other cities with a population of 500,000 or higher (Baltimore, Chicago, Cleveland, Philadelphia, Pittsburgh, and St. Louis). The 1920 census data was collected and tabulated by tract for these same cities. Dr. Laidlaw published the 1920 tract data for New York City. Chicago and Cleveland purchased and published their census tract data. The number of cities using census tracts expanded to eighteen (the same eight from 1910, along with Berkeley, Columbus, Los Angeles, Nashville, Syracuse, and Yonkers) by 1930. Starting with the 1940 census, the Census Bureau adopted the use of census tracts for all locations and started publishing census block or tract data for all cities with 50,000 or more inhabitants.

©2024 Kimberly Powell. Use of this article elsewhere without permission violates copyright. Short excerpts and links are welcome, with credit and a link back to Learn Genealogy.

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