Illicit Drug Flows and Seizures in the United States: In Focus
link to page 1 
August 1, 2019
Illicit Drug Flows and Seizures in the United States: In Focus
Policy discussions around issues such as border security,
The total amount of illicit drugs successfully smuggled
drug trafficking, and the opioid epidemic include questions
across the U.S. borders without being seized—at and
about illicit drug flows into the United States. While there
between land, air, and sea ports of entry (POEs)—is not
are numerous data points involved in understanding the
known with precision. However, there are data on the
trafficking of illicit drugs into the country, these data are
amount and locations of illicit drugs seized by border
often estimated, incomplete, imperfect, or lack nuance. For
officials.
more information, see CRS Report R45812, Illicit Drug
Flows and Seizures in the United States: What Do We [Not]
Figure 1. Illicit Drug Supply and Seizure Points
Know?
Illicit Drug Supply Chain
At the top of the illicit drug supply chain (see Figure 1) is
the total production of illicit drugs around the world—both
plant-based (e.g., cocaine, heroin, and marijuana) and
synthetic (e.g., methamphetamine and fentanyl). Although
some are produced in the United States, many originate
elsewhere and are smuggled into the country. For plant-
based drugs, a variety of factors affect cultivation as well as
surveillance and measurement of crop yields. In addition,
not all illicit drug crops may be processed into illicit drugs.
For synthetic drugs, the supply chain begins in chemical
manufacturing and pharmaceutical facilities. Measuring the
stock of these drugs is affected by issues including the
availability and inconsistent regulation of precursor
chemicals and the proliferation of synthetic analogues, or
new psychoactive substances.
Source: CRS representation of the general illicit drug supply chain
The next step in the supply chain of illicit drugs produced
and seizure points.
abroad and destined for the United States is their transit
Notes: The figure highlights drug seizure data that are used for
toward and into the country. Of the unknown total amount
policy debates around border security; however, these are not the
of illicit drugs produced, some may be consumed in the
only data policymakers rely upon in these discussions.
country of production, some may be destined for the United
States, and some may be intended for an alternate market.
Border Seizure Data
Of those drugs intended to be moved to the United States,
While a number of federal, state, local, and tribal agencies
some may become degraded or lost in transit, some may be
are involved in seizing illicit drugs in the border regions,
seized by law enforcement or otherwise destroyed or
the primary agency charged with safeguarding the U.S.
jettisoned by traffickers pursued by enforcement officials,
border, including seizing illicit drugs and other contraband,
and some reach the U.S. border.
is U.S. Customs and Border Protection (CBP). Within CBP,
Illicit Drugs Seized (or Not) at the
the Office of Field Operations (OFO) is responsible for
Border
staffing POEs, and drugs seized by OFO are generally
seized at POEs. In addition, the Border Patrol is responsible
As illicit drugs are brought to the U.S. border, they
for patrolling the land borders with Mexico and Canada,
generally fall into two initial categories: those that are
and the coastal waters surrounding Florida and Puerto Rico;
detected and seized by border enforcement officials and
drugs seized by the Border Patrol are generally drugs seized
those that are not. Those illicit drugs seized during inbound
between POEs. CBP data indicate that larger quantities (by
inspections are generally quantifiable. The largely unknown
weight) of cocaine, methamphetamine, heroin, and fentanyl
subset of drugs that enter the country without being seized
are seized at POEs than between the ports. Conversely, a
by officials during inbound inspections is divided into two
greater quantity of illicit foreign-produced marijuana is
categories: those that are later detected and seized by
seized between the ports.
federal, state, local, or tribal officials, and those that are not.
Notably, illicit drugs not seized at the border enter the
CRS analysis of OFO drug seizure data from FY2014 to
country where there are also domestically produced drugs.
FY2018 indicate that across those five years, about 65% of
As such, drugs that are later seized by officials in the
seized illicit drugs (by weight) were confiscated at land
United States may be of foreign or domestic origin.
POEs. In addition, about 28% of seized drugs were
https://crsreports.congress.gov
link to page 2 link to page 2
Illicit Drug Flows and Seizures in the United States: In Focus
confiscated at air POEs, and about 5% were seized at sea
illicit drugs. These estimates come from chemical testing
POEs (see Figure 2).
and analysis of certain drug samples, namely heroin,
cocaine, methamphetamine, and fentanyl. This analysis
Figure 2. OFO Drug Seizures FY2014-FY2018
helps determine, among other things, the primary source
Percentage seized by port of entry type
countries and/or methods of production.
Going Forward
Reliance on Border Drug Seizure Data
In the absence of comprehensive and precise data on illicit
drugs trafficked into the United States, seizure data can
provide some insight into elements of drug flows such as
smuggling points into and target markets within the
country. For instance, some have relied on selected border
seizure data to help understand the locations at which
federal enforcement efforts are stopping a portion of the
illicit drugs produced abroad from entering the country and
joining the domestic illicit drug market. However, a focus
on border seizures largely excludes a discussion of drug
Source: CRS analysis of CBP data provided on May 14, 2019.
seizures by law enforcement officials throughout the
Notes: OFO seizure data do not include Border Patrol data. The
interior of the country. As such, border seizures cannot
unknown/other category could involve OFO seizures of drugs during
speak to drug transportation and distribution throughout the
law enforcement operations occurring away from POEs or seizures
U.S. market or law enforcement priorities in the interior of
with uncertainty about how the drugs were moved through a POE.
the country. And because border seizures largely reflect
drugs detected during inbound inspections (and thus are
more likely to reflect foreign-produced drugs), a focus on
CRS analysis of OFO drug seizure data from FY2014 to
border seizures also largely excludes a discussion of illicit
FY2018 also indicate that nearly 97% of seized drugs were
drugs that are produced domestically.
confiscated during inbound inspections (see Figure 3).
Some 65% of seized drugs were seized during inbound
Enhancing Seizure Data Collection and Reporting
inspections at land POEs within the jurisdiction of the OFO
CBP is not the only agency that seizes illicit drugs in the
field offices along the Southwest border.
United States or even in the border regions. Federal, state,
Figure 3. OFO Drug Seizures FY2014-FY2018
local, and tribal law enforcement agencies are all involved
in enforcement actions that—even if not focused on drug-
Amount (in pounds) seized during inbound and outbound
related crimes—may involve drug seizures. Notably, there
inspections
is no central database housing information on all illicit drug
seizures from all law enforcement agencies (though the
Drug Enforcement Administration runs the National
Seizure System, containing data on drug seizures of certain
sizes made by specific federal agencies as well as other
voluntarily reported seizure data). If policymakers are
interested in having a more comprehensive view of drug
seizures throughout the United States, they could move to
enhance and consolidate existing data collection efforts.
Evaluating Border Risk Management and Drug
Trafficking-Related Strategies
The Department of Homeland Security uses a risk
management approach to help evaluate the diverse and
evolving threats—including drug smuggling—at the border.
Source: CRS analysis of CBP data provided on May 14, 2019.
Policymakers may question how officials use intelligence
Notes: OFO seizure data do not include Border Patrol data. The
about drug flows and data on drug seizures to assess the
unknown/neither category could involve drug seizures at a POE that
risks posed by drug smuggling and appropriately allocate
for certain reasons cannot be attributed to an inbound or outbound
resources to counter the threat. Congress may also evaluate
inspection as well as drug seizures during enforcement activities
how well available data on drug seizures can help measure
occurring away from official POEs.
progress toward achieving goals outlined in strategies like
the National Drug Control Strategy, aimed, at least in part,
Sourcing Drugs Seized in the United States
at reducing drug trafficking into and within the country.
While the quantities of illicit drugs that are successfully
smuggled into the country are unknown, U.S. officials look
Kristin Finklea, Specialist in Domestic Security
at illicit drugs seized in the United States and, in
IF11279
conjunction with drug intelligence, produce estimates of
which countries are the major suppliers of certain types of
https://crsreports.congress.gov
Illicit Drug Flows and Seizures in the United States: In Focus
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF11279 · VERSION 1 · NEW
August 1, 2019
Illicit Drug Flows and Seizures in the United States: In Focus
Policy discussions around issues such as border security,
The total amount of illicit drugs successfully smuggled
drug trafficking, and the opioid epidemic include questions
across the U.S. borders without being seized—at and
about illicit drug flows into the United States. While there
between land, air, and sea ports of entry (POEs)—is not
are numerous data points involved in understanding the
known with precision. However, there are data on the
trafficking of illicit drugs into the country, these data are
amount and locations of illicit drugs seized by border
often estimated, incomplete, imperfect, or lack nuance. For
officials.
more information, see CRS Report R45812, Illicit Drug
Flows and Seizures in the United States: What Do We [Not]
Figure 1. Illicit Drug Supply and Seizure Points
Know?
Illicit Drug Supply Chain
At the top of the illicit drug supply chain (see Figure 1) is
the total production of illicit drugs around the world—both
plant-based (e.g., cocaine, heroin, and marijuana) and
synthetic (e.g., methamphetamine and fentanyl). Although
some are produced in the United States, many originate
elsewhere and are smuggled into the country. For plant-
based drugs, a variety of factors affect cultivation as well as
surveillance and measurement of crop yields. In addition,
not all illicit drug crops may be processed into illicit drugs.
For synthetic drugs, the supply chain begins in chemical
manufacturing and pharmaceutical facilities. Measuring the
stock of these drugs is affected by issues including the
availability and inconsistent regulation of precursor
chemicals and the proliferation of synthetic analogues, or
new psychoactive substances.
Source: CRS representation of the general illicit drug supply chain
The next step in the supply chain of illicit drugs produced
and seizure points.
abroad and destined for the United States is their transit
Notes: The figure highlights drug seizure data that are used for
toward and into the country. Of the unknown total amount
policy debates around border security; however, these are not the
of illicit drugs produced, some may be consumed in the
only data policymakers rely upon in these discussions.
country of production, some may be destined for the United
States, and some may be intended for an alternate market.
Border Seizure Data
Of those drugs intended to be moved to the United States,
While a number of federal, state, local, and tribal agencies
some may become degraded or lost in transit, some may be
are involved in seizing illicit drugs in the border regions,
seized by law enforcement or otherwise destroyed or
the primary agency charged with safeguarding the U.S.
jettisoned by traffickers pursued by enforcement officials,
border, including seizing illicit drugs and other contraband,
and some reach the U.S. border.
is U.S. Customs and Border Protection (CBP). Within CBP,
Illicit Drugs Seized (or Not) at the
the Office of Field Operations (OFO) is responsible for
Border
staffing POEs, and drugs seized by OFO are generally
seized at POEs. In addition, the Border Patrol is responsible
As illicit drugs are brought to the U.S. border, they
for patrolling the land borders with Mexico and Canada,
generally fall into two initial categories: those that are
and the coastal waters surrounding Florida and Puerto Rico;
detected and seized by border enforcement officials and
drugs seized by the Border Patrol are generally drugs seized
those that are not. Those illicit drugs seized during inbound
between POEs. CBP data indicate that larger quantities (by
inspections are generally quantifiable. The largely unknown
weight) of cocaine, methamphetamine, heroin, and fentanyl
subset of drugs that enter the country without being seized
are seized at POEs than between the ports. Conversely, a
by officials during inbound inspections is divided into two
greater quantity of illicit foreign-produced marijuana is
categories: those that are later detected and seized by
seized between the ports.
federal, state, local, or tribal officials, and those that are not.
Notably, illicit drugs not seized at the border enter the
CRS analysis of OFO drug seizure data from FY2014 to
country where there are also domestically produced drugs.
FY2018 indicate that across those five years, about 65% of
As such, drugs that are later seized by officials in the
seized illicit drugs (by weight) were confiscated at land
United States may be of foreign or domestic origin.
POEs. In addition, about 28% of seized drugs were
https://crsreports.congress.gov
link to page 2 link to page 2
Illicit Drug Flows and Seizures in the United States: In Focus
confiscated at air POEs, and about 5% were seized at sea
illicit drugs. These estimates come from chemical testing
POEs (see Figure 2).
and analysis of certain drug samples, namely heroin,
cocaine, methamphetamine, and fentanyl. This analysis
Figure 2. OFO Drug Seizures FY2014-FY2018
helps determine, among other things, the primary source
Percentage seized by port of entry type
countries and/or methods of production.
Going Forward
Reliance on Border Drug Seizure Data
In the absence of comprehensive and precise data on illicit
drugs trafficked into the United States, seizure data can
provide some insight into elements of drug flows such as
smuggling points into and target markets within the
country. For instance, some have relied on selected border
seizure data to help understand the locations at which
federal enforcement efforts are stopping a portion of the
illicit drugs produced abroad from entering the country and
joining the domestic illicit drug market. However, a focus
on border seizures largely excludes a discussion of drug
Source: CRS analysis of CBP data provided on May 14, 2019.
seizures by law enforcement officials throughout the
Notes: OFO seizure data do not include Border Patrol data. The
interior of the country. As such, border seizures cannot
unknown/other category could involve OFO seizures of drugs during
speak to drug transportation and distribution throughout the
law enforcement operations occurring away from POEs or seizures
U.S. market or law enforcement priorities in the interior of
with uncertainty about how the drugs were moved through a POE.
the country. And because border seizures largely reflect
drugs detected during inbound inspections (and thus are
more likely to reflect foreign-produced drugs), a focus on
CRS analysis of OFO drug seizure data from FY2014 to
border seizures also largely excludes a discussion of illicit
FY2018 also indicate that nearly 97% of seized drugs were
drugs that are produced domestically.
confiscated during inbound inspections (see Figure 3).
Some 65% of seized drugs were seized during inbound
Enhancing Seizure Data Collection and Reporting
inspections at land POEs within the jurisdiction of the OFO
CBP is not the only agency that seizes illicit drugs in the
field offices along the Southwest border.
United States or even in the border regions. Federal, state,
Figure 3. OFO Drug Seizures FY2014-FY2018
local, and tribal law enforcement agencies are all involved
in enforcement actions that—even if not focused on drug-
Amount (in pounds) seized during inbound and outbound
related crimes—may involve drug seizures. Notably, there
inspections
is no central database housing information on all illicit drug
seizures from all law enforcement agencies (though the
Drug Enforcement Administration runs the National
Seizure System, containing data on drug seizures of certain
sizes made by specific federal agencies as well as other
voluntarily reported seizure data). If policymakers are
interested in having a more comprehensive view of drug
seizures throughout the United States, they could move to
enhance and consolidate existing data collection efforts.
Evaluating Border Risk Management and Drug
Trafficking-Related Strategies
The Department of Homeland Security uses a risk
management approach to help evaluate the diverse and
evolving threats—including drug smuggling—at the border.
Source: CRS analysis of CBP data provided on May 14, 2019.
Policymakers may question how officials use intelligence
Notes: OFO seizure data do not include Border Patrol data. The
about drug flows and data on drug seizures to assess the
unknown/neither category could involve drug seizures at a POE that
risks posed by drug smuggling and appropriately allocate
for certain reasons cannot be attributed to an inbound or outbound
resources to counter the threat. Congress may also evaluate
inspection as well as drug seizures during enforcement activities
how well available data on drug seizures can help measure
occurring away from official POEs.
progress toward achieving goals outlined in strategies like
the National Drug Control Strategy, aimed, at least in part,
Sourcing Drugs Seized in the United States
at reducing drug trafficking into and within the country.
While the quantities of illicit drugs that are successfully
smuggled into the country are unknown, U.S. officials look
Kristin Finklea, Specialist in Domestic Security
at illicit drugs seized in the United States and, in
IF11279
conjunction with drug intelligence, produce estimates of
which countries are the major suppliers of certain types of
https://crsreports.congress.gov
Illicit Drug Flows and Seizures in the United States: In Focus
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF11279 · VERSION 1 · NEW