What Is the Federal Age of Consent Under 18 U.S.C. § 2243?

The federal age of consent is 16 under 18 U.S.C. § 2243, but that number only decides cases in a narrow set of places: federal land, federal prisons and contract detention facilities, U.S.-flagged vessels, and U.S.-registered aircraft. Everywhere else, state law controls, and state ages of consent run from 16 to 18. Separate federal statutes also raise the protected age to 18 whenever the internet, a phone call, or interstate travel is part of the conduct, so the single federal number tells only part of the story.¹

Where the Age-16 Rule Applies

Section 2243 reaches conduct in the “special maritime and territorial jurisdiction of the United States.” That category covers federal enclaves the government owns or controls, including national parks, military installations, federal courthouses, and government buildings. It also covers U.S.-flagged vessels on international waters and U.S.-registered aircraft in flight over the high seas.²

The statute also applies inside every federal prison and inside any facility holding people in custody under contract with a federal agency. That third category is broader than it sounds. Privately operated detention centers, halfway houses, and immigration facilities holding people for the federal government are all included.¹

Anywhere outside those locations, the applicable rule is whatever the state has enacted. A sexual offense at a private home, a shopping center, or a state highway is a state matter, and the consent age depends on the state.

The 12-to-15 Window and the Four-Year Gap

Section 2243(a) makes it a federal crime to engage in a sexual act with someone who is at least 12 but younger than 16, provided the older person is at least four years older. Both conditions must be met. A 19-year-old and a 15-year-old cross the threshold. A 17-year-old and a 15-year-old do not.¹

The four-year gap is calculated from the actual birth dates at the time of the act, not rounded to the nearest year. A difference of three years and eleven months falls below the line. Four years and one day crosses it.

If the younger person is under 12, Section 2243 does not apply at all. The conduct is charged under 18 U.S.C. § 2241 as aggravated sexual abuse, which carries a mandatory minimum of 30 years and a maximum of life. A second conviction under that statute carries a mandatory life sentence.³

What Counts as a Sexual Act

A “sexual act” has a specific federal definition under 18 U.S.C. § 2246. It includes penetration, however slight, of the genitals or anus by any body part or object, along with oral-genital and oral-anal contact. When the younger person is under 16, it also includes intentional direct touching of the genitalia with intent to abuse, degrade, or sexually gratify. That last category does not require penetration; direct genital contact alone qualifies.⁴

The Mistake-of-Age Defense

Section 2243 includes an affirmative defense that most state statutes do not. Under subsection (d), a defendant can avoid conviction by showing they reasonably believed the other person was at least 16.¹

The burden falls on the defendant to prove that belief by a preponderance of the evidence, meaning more likely than not. Prosecutors do not have to disprove it. In practice, the defense is hard to win. A bare claim of “I thought they were older” rarely persuades a jury without something concrete behind it, like a fake ID presented before the encounter or documented misrepresentations of age.

The defense does not apply to charges under Section 2241 involving children under 12, and it does not apply to the ward or custody provisions of Section 2243, where age is not an element.

When the Federal Protected Age Is Really 18

Section 2243 draws the line at 16, but several other federal statutes protect anyone under 18 whenever interstate commerce or online communication is involved. Under 18 U.S.C. § 2422, using the internet, a phone, or any other means of interstate commerce to entice someone under 18 into sexual activity carries a mandatory minimum of 10 years and a maximum of life.⁵

18 U.S.C. § 2423 criminalizes transporting a person under 18 across state lines with intent that they engage in sexual activity, with the same 10-years-to-life range. It also reaches a U.S. citizen who travels to a foreign country to engage in sexual conduct with someone under 18, with a maximum of 30 years.⁶

Neither statute requires the conduct itself to occur on federal land. A text message, a phone call, or a state-line crossing is enough to trigger federal jurisdiction. Conduct that would be legal under Section 2243 because the younger person is 16 or 17 can still lead to a federal prosecution if the arrangement involved interstate communication or travel.

Penalties and Long-Term Consequences

A conviction under any subsection of Section 2243 carries a maximum of 15 years in federal prison.¹ Individual fines can reach $250,000.⁷

Prison time is followed by a mandatory term of supervised release. The minimum is five years, and the court can impose supervised release for life. Conditions during that period often include GPS monitoring, restrictions on internet use, and prohibitions on contact with minors.⁸

Federal law also requires sex offender registration under the Sex Offender Registration and Notification Act (SORNA). Registration length depends on tier: 15 years for Tier I, 25 years for Tier II, and life for Tier III.⁹ Tier I offenders can petition for a reduced period after 10 years of a clean record.¹⁰ A Section 2243 conviction is not explicitly listed as Tier II or Tier III under the Adam Walsh Act, so many defendants fall into Tier I by default, though actual classification can vary with the facts and the jurisdiction handling registration.

How State Law Fits In

Two rules govern the interaction between federal and state consent law. Off federal property, the state statute controls entirely; Section 2243 has no role. On federal property, state law can still reach conduct that Section 2243 does not cover. Under the Assimilative Crimes Act, criminal conduct on a federal enclave that no federal statute reaches can be prosecuted by borrowing the surrounding state’s law.¹¹ That matters when the parties are too close in age to trigger the four-year rule, or when the younger person is 16 or 17 and the surrounding state’s age of consent is higher. In those cases, federal prosecutors can apply the state statute on federal land.

1
Office of the Law Revision Counsel. 18 USC 2243 – Sexual Abuse of a Minor, a Ward, or an Individual in Federal Custody
2
Office of the Law Revision Counsel. 18 USC 7 – Special Maritime and Territorial Jurisdiction of the United States Defined
3
Office of the Law Revision Counsel. 18 USC 2241 – Aggravated Sexual Abuse
4
Office of the Law Revision Counsel. 18 USC 2246 – Definitions for Chapter
5
Office of the Law Revision Counsel. 18 USC 2422 – Coercion and Enticement
6
Office of the Law Revision Counsel. 18 USC 2423 – Transportation of Minors
7
Office of the Law Revision Counsel. 18 USC 3571 – Sentence of Fine
8
Office of the Law Revision Counsel. 18 USC 3583 – Inclusion of a Term of Supervised Release After Imprisonment
9
eCFR. 28 CFR 72.5 – How Long Sex Offenders Must Register
10
Office of Sex Offender Sentencing, Monitoring, Apprehending, Registering, and Tracking. Case Law Summary – SORNA Requirements
11
Office of the Law Revision Counsel. 18 USC 13 – Laws of States Adopted for Areas Within Federal Jurisdiction