The ACS Summary File is accessible from the American Community Survey main page. From the ACS main page, http://www.census.gov/acs/, click on the Data and Documentation tab, select the option for Summary File, as shown below:


That will take you to the ACS Summary File page. Click on 1-Year Summary File to go to the ACS Summary File ftp site:


This is the ACS Summary File-it is actually comprised of three folders that are explained the next chapter.

The Summary File is organized in three folders as shown in the above screenshot. These three directories contain the same combination of files; they are simply arranged differently to accommodate various user needs:

• ACSSF_All_In_1_Giant_File(Experienced-Users Only)
  ACSSF_All_In_2_Giant_Files(Experienced-Users-Only) (5-year release)

The"All in 1 Giant File" or "All in 2 Giant Files" directory contains a zipped file, which includes geography, estimate, and margin of error files. This zipped file is ideal to download if users want estimates and margins of error for all geographies throughout the nation at once. The file is very large and should only be used by those that can easily process a very large file.

• ACSSF_By_State_All_Tables

The "By State All Tables" directory contains folders for each state or state level equivalent, each of the 50 states, District of Columbia, Puerto Rico, as well as cross-state geographies such as metropolitan areas. Within those folders are a geography file and zipped files containing the estimate and margin of error files, one per "sequence" (sequences are explained in Chapter 2.3). Downloading from these folders is ideal if users only want a few tables for a state level geography or cross-state geographies.

• ACSSF_By_State_By_Sequence_Table_Subset

The "By State By Sequence Table Subset" directory contains folders for each state or state level equivalent-each of the 50 states, District of Columbia, Puerto Rico, as well as cross-state geographies such as metropolitan areas. Within those folders are a geography file and zipped files containing the estimate and margin of error files, one per "sequence" (sequences are explained in Chapter 2.3). Downloading from these folders is ideal if users only want a few tables for a state level geography or cross-state geographies. For a graphical representation of this folder and its contents, see Appendix B.3.

Using the 1-year release as an example, the naming convention used for the zipped files in this directory is the following:

File Name: 2013 1 ak 0001 000.zip
Example	Name	Range or Type
2013	Reference Year	ACS data year (last year of the period for multiyear periods)
1	Period Covered	1=1-year, 3=3-year, 5=5-year
ak	State Level	US or abbreviations for state, District of Columbia, and Puerto Rico
1	Sequence Number	0001 to 9999
0	IterationID	Iteration ID for Selected Population Tables and American Indian & Alaska Native Tables. Note: Iteration ID is always "000" for the standard 1-Year, 3-Year, and 5-Year products.

The "All in 1 Giant File" (or "All in 2 Giant Files") and the "By State All Tables" folders contain the same tables as the "By State By Sequence Table Subset" folder. The difference is in the organization. The "By State All Tables" zipped files contain all of the sequence files for the given state, so each zipped file contains over 300 files. The "All in 1 Giant File" (or "All in 2 Giant Files") zipped file contain all sequence files for all states, which is thousands of files.

As mentioned earlier, the zipped files are divided by state or state-level equivalents. Those state- level equivalents include the District of Columbia and Puerto Rico. There is also a level called "United States," which is for summary levels that can cross state boundaries, such as the Nation, and all Regions, Divisions, Metropolitan Statistical Areas and Tribal Reservations. The United States level does not contain tables for geographies that are always entirely within a state, such as counties and places; for those tables, go to the folder or files for that state.

The following is a table that gives examples of the types of summary levels are in the state and state-level equivalent folders and files and those that are in the United States folders and files.

Each State, DC, and Puerto Rico	United States
State	United States
County	Region
County subdivision	Division
Place	Metropolitan or urban statistical areas
Congressional districts (110th Congress)	New England City and Town Area (NECTA)
Public Use Microdata Area (PUMA)	American Indian/Alaska Native/Hawaiian Home Land areas
School Districts	Urban areas
Alaska Native Regional Corporation	Zip Code Tabulation Areas (ZCTAs)

Detailed Tables for similar subject areas are grouped together in "sequences". A sequence number is an assigned number to a grouping of ACS tables.

Table sequencing now follows these new rules:

1) Tables are sorted numerically by the "root" of their Table ID, where the "root" is defined as the numeric section after the first letter and before any additional letters, so for example the root of B06004APR is "06004".

For tables with the same root, additionally sort them in the following order:

Non-iterated, non-collapsed, non-PR version (e.g., Table B06003)
Iterated, non-collapsed, non-PR versions (e.g., Tables B06004A, B06004B...B06004I)
Non-iterated, collapsed, non-PR version (e.g., Table C06001)
Iterated, collapsed, non-PR version (e.g., Tables C08505A, C08505B... C08505I)
Non-iterated, non-collapsed, PR version (e.g., Table B06003PR)
Iterated, non-collapsed, PR versions (e.g., Tables B06004APR, B06004BPR... B06004IPR)
Non-iterated, collapsed, PR version (e.g., Table C06001PR)
Iterated, collapsed, PR version (e.g., Table C06001APR)

2) With tables sorted in this order, start with the first table and assign it to the first sequence. For each subsequent table, if the table has either a new "subject," a new "geography type," or would cause the number of cells in the sequence to exceed 245, then start a new sequence. "Subject" is described using the second and third characters in the Table ID, so for example the subject of B06004APR is "06" for place of birth. You can view a complete list of subjects at ask.census.gov/faq.php?id=5000&faqId=1687.

"Geography type" can be one of three things:

Place of Residence geography type,
Place of Work geography type, or
Residence 1 Year Ago geography type.

3) If a table does not fit in one sequence, then put the first 245 cells of it in one sequence, and the rest in the next. If a table does not fit in two sequences, then put the first 245 cells of it in one sequence, the next 245 cells of it in the next sequence, and the rest in a third sequence. The rules governing how many tables can be assigned the same sequence number depend on the following:

• There are no more than 256 cells per sequence, so the data can be read into a spreadsheet. There are 245 data cells and 11 other cells reserved for identifying information.
• There are approximately 170+ sequences for the 2013 ACS 1-year Summary File, approximately 170+ sequences for the 2011-2013 ACS 3-year Summary File, and approximately 120+ sequences for the 2009-2013 ACS 5-year Summary File.
• Tables are grouped numerically by the "root" of their Table ID, (i.e., Table B00001 is in sequence file 0001).
• Tables with race iterations are grouped in the same sequence.

It is critical to know the sequence number associated with a Detailed Table (Table ID) for two reasons. First, one needs it in order to access the correct estimates and margins of error files for the desired table. Second, the field start position for the estimates or margins of error of a certain Detailed Table depends on its sequence number. The Sequence Number and Detailed Table Number Lookup file, available as an Excel spreadsheet, text file, and SAS dataset, lists Table IDs associated with each sequence number. This spreadsheet is available on the ACS Summary File page at www.census.gov/acs/www/data_documentation/summary_file/.

For example, to find the sequence number associated with the table B08406, a user must open and look for that Table ID in the Sequence Number and Table Number Lookup file. Shown below is a screenshot of this file opened to where the "tblid" is B08406. The next column in the file, "seq", shows that this Table ID is associated with the sequence number "0029". In order to access the estimate and margin of error file for Table B08406, a user will need to download the estimate and margin of error files labeled with the sequence number "0029".

There is a geography file that comes with the estimate and margin of error files. This file begins with a "g" and is an ASCII file using either a position based format or comma delimited format. A geography file exists for each state or state level equivalent.

Geography files are named using the following convention (using the 1-year data release as an example):

File Name: g 2013 1 ak.txt
Example	Name	Range or Type
g	File Type	g=geography
2013	Reference Year	ACS data year (last year of the period for multiyear periods)
1	Period Covered	1=1-year, 3=3-year, 5=5-year
ak	State Level	US or abbreviations for state, District of Columbia, and Puerto Rico

The geography files contain geographic information for an ACS tabulated area, including the name of the area. One variable on the file, called LOGRECNO, is the logical record number and is used to link the level of geography to the estimate and margin of error files. An example of how to use LOGRECNO is discusses in Chapter 2.5.The fields in the layout below are blank if the geography is not available for a release.
The following table provides the generic layout of the geography file (1,3,5-Year):

Variable Name	Description	Field Size	Starting Position
RECORD CODES
FILEID	Always equal to ACS Summary File identification	6	1
STUSAB	State Postal Abbreviation	2	7
SUMLEVEL	Summary Level	3	9
COMPONENT	Geographic Component	2	12
LOGRECNO	Logical Record Number	7	14
GEOGRAPHIC AREA CODES
US	US	1	21
REGION	Census Region	1	22
DIVISION	Census Division	1	23
STATECE	State (Census Code)	2	24
STATE	State (FIPS Code)	2	26
COUNTY	County of current residence	3	28
COUSUB	County Subdivision (FIPS)	5	31
PLACE	Place (FIPS Code)	5	36
TRACT	Census Tract	6	41
BLKGRP	Block Group	1	47
CONCIT	Consolidated City	5	48
AIANHH	American Indian Area/Alaska Native Area/ Hawaiian Home Land (Census)	4	53
AIANHHFP	American Indian Area/Alaska Native Area/ Hawaiian Home Land (FIPS)	5	57
AIHHTLI	American Indian Trust Land/ Hawaiian Home Land Indicator	1	62
AITSCE	American Indian Tribal Subdivision (Census)	3	63
AITS	American Indian Tribal Subdivision (FIPS)	5	66
ANRC	Alaska Native Regional Corporation (FIPS)	5	71
CBSA	Metropolitan and Micropolitan Statistical Area	5	76
CSA	Combined Statistical Area	3	81
METDIV	Metropolitan Statistical Area-Metropolitan Division	5	84
MACC	Metropolitan Area Central City	1	89
MEMI	Metropolitan/Micropolitan Indicator Flag	1	90
NECTA	New England City and Town Area	5	91
CNECTA	New England City and Town Combined Statistical Area	3	96
NECTADIV	New England City and Town Area Division	5	99
UA	Urban Area	5	104
BLANK		5	109
CDCURR	Current Congressional District ***	2	114
SLDU	State Legislative District Upper	3	116
SLDL	State Legislative District Lower	3	119
BLANK		6	122
BLANK		3	128
ZCTA5	5-digit ZIP Code Tabulation Area	5	131
SUBMCD	Subminor Civil Division (FIPS)	5	136
SDELM	State-School District (Elementary)	5	141
SDSEC	State-School District (Secondary)	5	146
SDUNI	State-School District (Unified)	5	151
UR	Urban/Rural	1	156
PCI	Principal City Indicator	1	157
BLANK		6	158
BLANK		5	164
PUMA5	Public Use Microdata Area - 5% File	5	169
BLANK		5	174
GEOID	Geographic Identifier	40	179
NAME	Area Name	1000	219
BTTR	Tribal Tract	6	1219
BTBG	Tribal Block Group	1	1225
BLANK		43	1226

We also provide an Excel template for the geography file named "SFGeoFile Template.xls." The template provides users with two rows containing the variable names and their descriptions (as displayed in the above table) for each column in the geography file. It is meant to be used with the comma delimited version of the geography file. The template is available in the User Tools folder for your dataset (i.e., www2.census.gov/acs2013_1yr/summaryfile/UserTools/ in the zipped "2013_SummaryFileTemplates" folder). Here is a screenshot of the Excel file:



Each state, the District of Columbia, Puerto Rico and the set of cross-state geographies, have one geography file associated with them regardless of how the Summary File is accessed. For example, the following screenshot shows the beginning of the state geography file for Maryland. In the screenshot, the logical record numbers corresponding with the state of Maryland, Allegany County, and Anne Arundel County are circled. The logical record number for the state of Maryland is "0000001", for Allegany County it is "0000012", and for Anne Arundel County it is "0000013".


Excess spaces in the pictured geography file have been removed for illustrative purposes.

Each of the three Summary File directories include zipped files containing estimate files (file names beginning with an "e") and margins of error files (file names beginning with an "m"). The estimate files contain published ACS estimates and the margin of error files contain published ACS margins of error for their respective estimates. Here is the naming convention used for those files (using the 1-year data release as an example):

File Name: e 2013 1 ak 0001 000.txt
Example	Name	Range or Type
e	File Type	e=estimate, m=margin of error
2013	Reference Year	ACS data year (last year of the period for multiyear periods)
1	Period Covered	1=1-year, 3=3-year, 5=5-year
ak	State Level	US or abbreviations for state, District of Columbia and Puerto Rico
3	Sequence Number	0001 to 9999
0	Reserved for future use	Iteration value for future use

The estimates and margins of error for Detailed Tables are grouped together in by sequence numbers, as discussed in Chapter 2.3. There is an estimate and margin of error file for each sequence number.

The format of the estimate and margin of error files are identical; they are strings of comma- delimited ASCII text. Each row represents a different geographic area and the first six fieldscontain metadata such as the geographic area and the sequence number. Following those fields are the estimates or margins of error for the Detailed Tables. Starting and ending positions of the fields associated with each Detailed Table can be found using the Sequence Number and Table Number Lookup file, which is discussed in Chapter 2.3. The estimates or margins of error for one Detailed Table span several fields within a row.

Here is the record layout of the estimates and the margin of error files:

Field Name	Description	Field Size
FILEID	File Identification	6 Characters
FILETYPE	File Type	6 Characters
STUSAB	State/U.S. - Abbreviation (USPS)	2 Characters
CHARITER	Character Iteration	3 Characters
SEQUENCE	Sequence Number	4 Characters
LOGRECNO	Logical Record Number	7 Characters
Field # 7 and up	Estimates	Various

Going back to the example from Chapter 2.3, we know that table B08406 corresponds to sequence "0029". Additionally, the Sequence Number and Table Number Lookup file (as shown earlier) tells us that table B08406 begins at position seven and contains 51 cells.

In order to get estimates for Maryland; Allegany County, MD; and Anne Arundel County, MD one must recall the logical record numbers associated with each geography. In Chapter 2.4, we identified these to be "0000001", "0000012", and "0000013", respectively. The logical record number, LOGRECNO, must be used to merge the geography information to the estimate and margin of error files.

The example below shows the estimate file for sequence "0029" and all geographies except census tracts and block groups for the state of Maryland using the 2007-2009 ACS 3-year Summary File. For the2008-2012 ACS 5-year Summary File, the dots "." in the below screenshot will be replaced by empty cells as documented in Chapter 4.2.. Note that each row has a uniquely assigned logical record number, called LOGRECNO, which links the estimate to a specific geographic area. The pictured example has the logical record numbers corresponding to Maryland, Allegany County, and Anne Arundel County circled. Estimates for table B08406 at these geographic levels can be found within their respective rows at field seven and continuing for 50 additional fields.