Stopping illegal immigration in the United States is not a single policy but a stack of them: physical barriers and surveillance at the border, systems to catch visa overstays, interior arrests and detention by ICE, cooperation agreements with state and local police, employer verification requirements, narrowed asylum processing, criminal penalties for unauthorized entry and reentry, and long-term bars on future admission for anyone who accumulated unlawful presence. Since January 2025, federal policy has shifted toward what the White House calls “total and efficient enforcement” against all removable individuals, replacing the narrower priority-based approach used in prior years.1The White House. Protecting the American People Against Invasion That change runs through nearly every tool below.
Border Barriers and Surveillance
Physical barriers do one thing well: they slow people down long enough for Border Patrol to respond. Pedestrian fencing, vehicle barriers, patrol roads, and lighting work together in high-traffic corridors. No wall stops every crossing on its own, but time is the critical variable when an agent may be miles away.
Technology fills the gaps fencing cannot. Customs and Border Protection deploys autonomous surveillance towers powered by solar energy, each roughly 33 feet tall and capable of monitoring an area about three miles across. Radar scans continuously, and when it detects movement, artificial intelligence directs day and night cameras to track and classify the source. Towers hand targets off to one another as groups move.2U.S. Customs and Border Protection. A Watchful Eye Hundreds have been deployed or planned across Texas and southern California, supplemented by ground sensors in remote terrain and unmanned aerial systems.
Catching Visa Overstays
A large share of unauthorized immigration is not illegal crossing at all. People enter legally on tourist, student, or work visas and never leave. In fiscal year 2023, CBP recorded about 565,000 overstay events out of roughly 39 million expected departures at air and sea ports, a total overstay rate of 1.45 percent, with more than 510,000 individuals suspected of still being in the country at year end. Rates vary sharply by category: Visa Waiver Program visitors overstayed at 0.62 percent, non-waiver business and tourist visitors at 3.20 percent, and student and exchange visitors at 3.67 percent.3Department of Homeland Security. Entry/Exit Overstay Report, Fiscal Year 2023
CBP has fully implemented facial comparison at arrival in the air, sea, and pedestrian land environments. Biometric exit is running at select airports through airline partnerships, with CBP still refining its approach for land borders and private aircraft.4Federal Register. Collection of Biometric Data From Aliens Upon Entry to and Departure From the United States Matching a face at entry against a face at departure creates a reliable record of who actually left; without it, identifying overstays depends on the absence of a departure record.
To deter overstays before they happen, the State Department expanded its visa bond program in 2026 to cover 50 countries. Nationals of those countries applying for business or tourist visas must post a $15,000 bond, refunded only on timely departure. State reports that 97 percent of bonded travelers have returned home as required.5U.S. Department of State. State Department Expands Visa Bonds to Combat Illegal Overstay Rates
Interior Enforcement and Detention
Immigration and Customs Enforcement handles enforcement inside the country. The scope of that enforcement has changed significantly. Under the prior administration, ICE operated under a tiered priority system that concentrated resources on individuals posing national security or serious public safety threats, weighing mitigating factors like family ties before pursuing others. That framework was revoked on January 20, 2025, when Executive Order 14159 directed agencies to “employ all lawful means to ensure the faithful execution of the immigration laws of the United States against all inadmissible and removable aliens.”1The White House. Protecting the American People Against Invasion In practice, ICE is no longer instructed to pass over lower-priority individuals encountered during operations. The same order redirected Homeland Security Investigations to make immigration enforcement a primary mission alongside its work on transnational crime and smuggling.
Congress added new mandatory detention requirements. The Laken Riley Act, signed on January 29, 2025, requires DHS to detain any individual who is unlawfully present and has been charged with, arrested for, or convicted of burglary, theft, larceny, or shoplifting.6Congress.gov. S.5 – Laken Riley Act, 119th Congress (2025-2026) Detention is triggered at the point of charge or arrest, not conviction. The immigration court system that processes removal cases carries a backlog of roughly 3.4 million pending cases, which shapes how quickly any enforcement action becomes an actual removal.
State and Local Cooperation
Federal immigration authorities cannot be everywhere. The 287(g) program deputizes state and local officers to perform certain immigration functions under ICE supervision. As of late March 2026, ICE had signed 1,579 agreements covering agencies in 39 states and two U.S. territories, an expansion driven by Executive Order 14159’s instruction to authorize state and local participation “to the maximum extent permitted by law.”7U.S. Immigration and Customs Enforcement. Delegation of Immigration Authority Section 287(g) Immigration and Nationality Act
Participating agencies operate under one or more agreement types. The Jail Enforcement Model has officers identify and process removable individuals already in local custody on criminal charges. The Task Force Model gives officers limited immigration authority during routine police work. The Warrant Service Officer model has officers serve and execute ICE administrative warrants on individuals held in local jails. All operate under ICE oversight and training requirements.
Separately, federal law prohibits any government entity from restricting immigration status information sharing with federal authorities. Under 8 U.S.C. 1373, no state, local, or federal agency may prevent its employees from sending or receiving immigration status information to or from immigration authorities.8Office of the Law Revision Counsel. 8 USC 1373 – Communication Between Government Agencies and the Immigration and Naturalization Service That baseline applies whether or not a jurisdiction has entered a 287(g) agreement.
Employer Verification and Sanctions
Jobs are the primary draw for most economic migration, so work authorization checks are one of the main deterrents. Every U.S. employer must complete Form I-9 for each new hire, verifying identity and work eligibility from specified documents.9U.S. Citizenship and Immigration Services. I-9, Employment Eligibility Verification The employee fills out the first section on day one, and the employer completes verification within three business days of hire.10E-Verify. E-Verify User Manual – 2.1 Form I-9 and E-Verify
E-Verify adds an electronic check on top of the paper I-9. Employers submit new hire information to be matched against DHS and Social Security Administration records. Participation is mandatory for federal contractors and in a growing number of states that require it, but remains voluntary for most private employers nationwide.
Federal law makes it illegal to knowingly hire an unauthorized worker or to continue employing someone after learning they lack authorization. Employers who fail to properly complete or retain I-9 forms face civil fines for each deficient form. Knowingly hiring unauthorized workers carries heavier penalties that escalate with repeat violations, and the statute authorizes criminal prosecution for a pattern or practice of violations. Employers must retain verification forms for either three years after the hire date or one year after the employee leaves, whichever is later.11Office of the Law Revision Counsel. 8 USC 1324a – Unlawful Employment of Aliens
Narrowing Asylum as a Pathway
Asylum law allows someone physically present in the United States or arriving at a port of entry to seek protection if they face persecution based on race, religion, nationality, political opinion, or membership in a particular social group. Someone subject to expedited removal who expresses a fear of return receives a credible fear screening, which asks whether there is a “significant possibility” they can establish eligibility for asylum based on a well-founded fear of persecution on one of those protected grounds.12U.S. Citizenship and Immigration Services. Questions and Answers – Credible Fear Screening
Since early 2025, asylum processing has been substantially modified. DHS imposed a broad hold on asylum adjudications and has been selectively lifting it by country, resuming decisions for applicants from nations not classified as high-risk while maintaining the pause for roughly 40 other countries. The administration has also proposed new regulations that would make employment authorization for asylum applicants discretionary rather than automatic and terminate work permits immediately after an asylum denial.13Federal Register. Employment Authorization Reform for Asylum Applicants These changes are aimed at reducing incentives to file asylum claims as a route to long-term residence.
Criminal Penalties for Entry, Reentry, and Smuggling
Removal is administrative, but federal law also attaches criminal penalties to unauthorized crossing and return. A conviction means a federal record, potential imprisonment, and much worse consequences for anyone who tries to come back.
Improper Entry
A first offense of entering outside a designated port of entry, evading inspection, or gaining entry by misrepresentation is a federal misdemeanor punishable by up to six months in prison, a fine, or both. A second or subsequent offense is a felony carrying up to two years.14Office of the Law Revision Counsel. 8 USC 1325 – Improper Entry by Alien First-time crossers in many sectors have historically been processed administratively rather than criminally, though the current enforcement posture has expanded criminal referrals.
Illegal Reentry After Removal
Returning after deportation is a more serious offense, with penalties scaling to the person’s criminal history: up to 2 years for basic reentry; up to 10 years after prior removal following three or more misdemeanors involving drugs or crimes against people, or a non-aggravated felony; up to 20 years after prior removal following an aggravated felony; and a mandatory 10-year sentence, which cannot run concurrently with any other sentence, after prior removal on terrorism-related grounds.15Office of the Law Revision Counsel. 8 USC 1326 – Reentry of Removed Aliens The Sentencing Commission has found that about 40 percent of illegal reentry offenders had criminal histories serious enough to trigger the 20-year statutory maximum, though virtually all were sentenced at or below 10 years.16United States Sentencing Commission. Illegal Reentry Offenses
Smuggling and Harboring
Federal law imposes steep penalties on anyone who helps others enter or remain in the country illegally. Smuggling someone in for profit carries 3 to 10 years for a first or second offense, escalating to 5 to 15 years for subsequent violations. Harboring, concealing, or shielding an unauthorized individual from detection is punishable by up to 5 years, or up to 10 years when done for financial gain. If any of these acts cause serious bodily injury, the maximum jumps to 20 years. If someone dies as a result, the penalty can be life in prison or death.17Office of the Law Revision Counsel. 8 USC 1324 – Bringing in and Harboring Certain Aliens
These smuggling statutes target the networks that move people, not the people they exploit. Victims of human trafficking, often controlled by those same networks, have a separate pathway through the T visa if they cooperate with law enforcement, with exceptions for minors and those unable to cooperate because of trauma.18U.S. Citizenship and Immigration Services. Victims of Human Trafficking – T Nonimmigrant Status
Bars on Future Admission
Even after someone leaves voluntarily, accumulated unlawful presence triggers automatic bars on legal return. The three-year bar applies to anyone unlawfully present for more than 180 days but less than one year who departs and seeks readmission within three years. The ten-year bar applies to anyone unlawfully present for one year or more who departs and seeks readmission within ten years.19Office of the Law Revision Counsel. 8 USC 1182 – Inadmissible Aliens
These bars create a difficult trade-off. Someone who has been in the country without status for years and wants to legalize through a family petition or employer sponsorship typically must leave to process the visa at a consulate abroad. The moment they depart, the ten-year bar attaches. Waivers exist but are hard to obtain, generally requiring proof of extreme hardship to a qualifying U.S. citizen or permanent resident relative. The practical effect is to discourage future unauthorized entry and to lock in the consequences of unlawful presence already accrued.