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ACS Summary File

The American Community Survey (ACS) Summary File is a unique data product that includes all estimates and margins of error (MOE) from the Detailed Tables for all geographies published for the ACS. The ACS Summary File allows data users to download statistics for a large number of tables and geographic areas. 

Table-Based Format

For the 2018 data release, the Census Bureau tested a new, Table-Based Format for the ACS Summary File. This format groups the estimates and MOE by table ID, removing the need to merge these files. That is, a file is posted for each table containing both the estimates and MOE for all available geographies. Data users only need to merge in geography labels to create complete tables.

The Table-Based Format is the only format for the 2022 data release, and it will be the only format going forward. Check out the Getting Started and data year tabs below for information and resources. The resources include instructions for merging the geography labels with each table via Excel or programs like SAS and Python. 

To share feedback on the Table-Based Format, please send your comments to acso.users.support@census.gov and title your message “ACS Summary File Feedback.” We appreciate hearing about what you like or what we can improve.

Changes for the 2022 Data Release

Starting with the 2022 data release, the Table-Based Format is the only format available.The 2021 data release was the final release of the original Sequence-Based Format; it is available for years 2005 through 2021. More information, including data, instructions and example programs are located on the ACS Summary File Sequence-Based Format page. 

Getting Started
  • Getting Started
  • 2022
  • 2021
  • 2020
  • 2019
  • 2018
  • 2017 to 2005
Getting Started

The Table-Based ACS Summary File contains three file types:

Table Labels - Description of each line item in a table for 1-year or 5-year data release

    Example File Name: ACS20211YR_Table_Shells.txt or      ACS20215YR_Table_Shells.txt
    Example: B01001_003 = “SEX BY AGE - Total Males Under 5 Years”

​Geography Labels - All geography labels for 1-year or 5-year data release

    Example File Name: Geos20211YR.txt or Geos20215YR.txt 
    Example: 0400000US06 = “California”

Data Files - Data (including estimates, margins of error, and geographies) organized by table ID for 1-year or 5-year release
    Folder: 1YRData, 5YRData
    Example: The file acsdt1y2021-b01001.dat, variable B01001_E003      for 0400000US06 = 1,129,355

There are a variety of resources available for understanding and using the table-based format. Linked below are webinars related to the table-based format, link to the FTP site to access data and documentation, instructions using geography files with the summary file, and links to the ACS Summary File GitHub page offering further guidance on the table-based format as well as examples for using SAS and Python.    

Summary File Data

2021-Present: Select the table-based folder to find table-based format. 2018-2020: Select the Prototype folder to select the table-based format. Summary file data from 2005 to 2017 only had the sequence-based format.

Release Notes and Supporting Materials

Visit the ACS Summary File GitHub wiki page for notes on data, geography, variable changes, example code, and other important general information about the table-based format.

Page Last Revised - October 24, 2023
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