Boundary and Annexation Survey

Boundary and Annexation
Survey (BAS)
What is the Boundary and Annexation Survey?
The Boundary and Annexation Survey (BAS) is the primary way that
local, county, and tribal governments ensure that their legal boundaries—and
consequently, their official population counts—are correctly recorded with the
federal government. Every year, governments use the BAS to update their legal
boundaries and official names.
In the BAS, governments report official name changes,
(dis)incorporations, and (de)annexations. Governments can
also update boundaries, features, and landmarks for:
• Cities, towns, boroughs, and villages (incorporated places)
• Townships and towns (minor civil divisions)
• Counties (or county equivalents)
• Consolidated cities
• Roads and other applicable linear features

Find forms, information, and
materials about the BAS online at
.
Contact us at
or
1-800-972-5651.

How does the BAS benefit you?
Legal boundaries determine your government’s population count every year in
the American Community Survey and the Population Estimates Program. Many
government agencies and other groups use population counts to determine the
allocation of funds. Responding to the BAS ensures that your local government
has the best data available for its decision-making processes, and that it
receives all of the funds for which it is entitled.
In addition, our boundary records are publicly available and used by
many other federal agencies, researchers, and the public. Because
the U.S. Census Bureau is responsible for tracking America’s legal
boundaries and population data, geographic updates that you
provide to us ripple out in numerous important ways.

Accurate boundary records directly affect
the quality of life in your community.
Accurate boundaries allow
us to count your community’s
residents accurately.

Your participation in the BAS
helps the Census Bureau
continue to produce accurate
data, which directly affects the
quality of life in your community.

An accurate count helps the federal
government allocate more than
$675 billion in federal funds annually
for programs and services—including
education, housing, health care
services for the elderly, job training,
transportation, and more.

Connect With Us

Responding to the BAS is easy.
The Census Bureau provides multiple free, user-friendly methods for
responding to the BAS.
Paper option
BAS participants can request free paper maps from the BAS Web site.
Basic digital option
The Geographic Update Partnership Software (GUPS) is a free, customized
Geographic Information Systems (GIS) tool that will be available during the
BAS. It was specifically developed for people who do not have geographic
training or are not experienced GIS users.
Advanced digital option
Experienced GIS users can update boundaries in their own GIS. The Census
Bureau provides free GIS files in shapefile format on its Web site, along with
digital update guidelines. Governments can update those shapefiles in their GIS
and use them to respond to the BAS.

To make responding to the BAS as easy
as possible, we’ve created a YouTube
channel with videos to walk you through
the survey.
Visit .

To see the existing boundaries that we
have on file for your community, visit the
Census Bureau’s online map application at
.

Will the Census Bureau contact my
government for the BAS program?
Every year, the Census Bureau will send the BAS to
key contacts for every government affected by the
survey:
• The government’s highest-elected official, such as
the mayor or county executive.
• A GIS staff, planner, clerk, or other contact that the
government instructs us to contact.
• The relevant state-level official.

Version 3, 11/15/2017

BAS Schedule
January: The Census Bureau
e-mails annual response information
to BAS contacts with instructions for
participation.
March 1(first deadline): Legal
boundary updates (not including
nonlegal boundary corrections) sent
by this date are included in the next
Population Estimates Program and
American Community Survey
shapefiles and population
estimates.
May 31(final deadline): Boundary
updates sent by this date will
appear in the next year’s BAS
shapefiles.