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 tribal,
local, and county governments ensure that their legal boundaries—and
consequently, the official population counts within those boundaries—are
correctly recorded with the federal government. Every year, tribal governments
use the BAS to update their federal reservation and off-reservation trust land
boundaries.
In the BAS, tribal governments report new land and
update boundaries, features, and landmarks for:
•
•
•
•

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

Federal reservations
Off-reservation trust lands
Tribal subdivisions
Roads

How does the BAS benefit you?
Accurate legal boundaries are part of the foundation of good decision-making
for tribal governments. For example, they help determine your community’s
population count every year in the American Community Survey. Many
government agencies and other groups use population counts to determine
their allocation of funds. Responding to the BAS ensures that your tribe has
the best data available in 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 all of the residents of
your reservation and offreservation trust land correctly.

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
Tribes 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
tribe for the BAS program?
In recognition of tribal sovereignty, the Census Bureau
works government to government with federally
recognized tribes and contacts the following every
year.
• The tribal chairperson.
• A GIS staff, planner, clerk, or other contact that the
tribe instructs us to contact.
• National American Indian Housing Council members

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 sent by this date
are included in the next 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 and maps.