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Census 2000 Summary File 3 ASCII text data files

ASCII data set information
Deciding which data files to use
Using Microsoft Access
Using SAS
Using other database programs
Data file directory
File documentation [PDF, 4.34 MB]
Census 2000 Data Products support

ASCII data set information

A data set consists of one geographic identifier file and seventy six data files. The Geo ID file should initially appear last in the data directory and will contain "geo" as part of its' filename. The Geo ID file is not a "header file" as it is linked horizontally with the data files, not placed on top of them vertically. Any data file used must be linked to the Geo ID file (on the unique key field LOGRECNO 1) because the data files do not contain any geographic identifiers. Each data file contains a different set of demographic data tables.

None of the files contain a header record (first record or row with field names). Microsoft Access and SAS templates and instructions are provided to assist in importing the ASCII text files into these programs. The Geo ID file is fixed width with no field delimiters while all seventy six data files are variable length with comma field delimiters.

The field SUMLEV 2 in the Geo ID file identifies the summary level (area type) of each record. A combination of the geographic identifier codes for each element in the complete summary level description is used to identify the specific area being tabulated. 100% housing unit and population counts are also contained in the geographic ID file.


1 LOGRECNO has no other signifigance. There is a one to one correspondence based on LOGRECNO between the Geo ID file and data files 01 - 18 and 56 - 62 only. Data files 19 - 55 are made up of PCT tables (population tables down to the census tract level) and data files 63 - 76 are made up of HCT tables (housing tables down to the census tract level).

2 Chapter 4 (Summary Level Sequence Chart) of the file documentation contains a code list for SUMLEV (summary level) along with possible values for GEOCOMP (geographic component) for each summary level (area type for which summary data is available). Separate charts are included for the state files and the national file. See the Footnote Section of Chapter 7 to see a code list for GEOCOMP.

The Data Dictionary Section of Chapter 7 includes the geographic ID file's record layout. The Table Matrix Section of Chapter 7 contains a complete demographic data table information including all properly indented headings, the universe, and all data items. See Appendix A for definitions of geographic terms. It is recommended that GIS users also see notes on using boundary files.

[Back to Top]Deciding which data files to use

See Chapter 3 Subject Locator in the file documentation to identify table numbers of interest.

See Chapter 2 How to Use This File Figure 2-2 to identify the data files(s) that contain these tables.

See Chapter 7 Data Dictionary Table Matrix Section to see a complete list of data items contained in these tables. The complete table including the title, universe, all headings and data items is shown.

The steps above complete the data file selection process.

File documentation [PDF, 4.34 MB]

[Back to Top]Using Microsoft Access

Download Summary File 3 template file (Access 2000 format) provided here to get started. Next, open it in Microsoft Access and follow these procedures to import the SF3 ASCII data and attach the header (field name) information.

Also see technical notes about recent updates to the Access template.

[Back to Top]Using SAS

Download SAS programs or contact your local state data center (SDC) for an alternate version of the SAS code. SPSS code may also be available from your local SDC. The SAS programs convert the ASCII text data files to SAS data sets. Light modifications such as changing the input and output file names and the directories used to store data may need to be made.

SF3GEO.SAS - Converts the geographic identifier file

SF3xx.SAS - Converts the matching (by number) data file number and merges this with SAS data set created by SF3geo.sas. There are seventy-six of these files numbered from SF301.sas to SF376.sas. Go to additional SAS instructions for more information.

[Back to Top]Using other database programs

This section assumes familiarity with operations in database management programs such as opening a data table and appending records to it as well as setting up a relationship between two data tables based on a common field.

FoxPro format layouts [ZIP, 274 KB]
Oracle Link to a non-federal Web site (Google search)
SPSS Link to a non-federal Web site (Google search)

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Source: U.S. Census Bureau | Administrative and Customer Services Division | (301) 763-7710 |  Last Revised: February 13, 2013