It is a federal crime to make a material false statement in a matter within the jurisdiction of a federal agency or department. Finally, conspiracy to commit any these underlying crimes is also a separate federal crime. This is an overview of federal law relating to the principal false statement and to the three primary perjury statutes. Within the judicial branch, it applies to all but presentations to the court by parties or their attorneys in judicial proceedings. In outline form, Section 1001(a) states:
I. One proscribes false statements in matters of legislative branch administration and reaches false statements made in financial disclosure statements. § 1621(2))

Congress added Section 1621(2) to the general perjury statute in 1976 in order to dispense with the necessity of an oath for various certifications and declarations. Perjury in a Judicial Context (18 U.S.C. § 371)

Section 371 outlaws conspiring to commit another federal offense, including making a false statement in violation of Section 1001, perjury under Sections 1621 and 1623, and subornation of perjury under Section 1622. Conspiracy under Section 371 is punishable by imprisonment for not more than five years. § 3C1.1)

Perjury, subornation of perjury, and false statements are each punishable by imprisonment for not more than five years. When the defendant is convicted of a crime other than perjury or false statements, however, perjury or false statements during the investigation, prosecution, or sentencing of the defendant for the underlying offense will often be treated as the basis for enhancing his sentence by operation of the obstruction of justice guideline of the U.S. The examples in the section's commentary cover conduct: 
(B) committing, suborning, or attempting to suborn perjury, including during the course of a civil proceeding if such perjury pertains to conduct that forms the basis of the offense of conviction;
(F) providing materially false information to a judge or magistrate;
(G) providing a materially false statement to a law enforcement officer that significantly obstructed or impeded the official investigation or prosecution of the instant offense;
(H) providing materially false information to a probation officer in respect to a presentence or other investigation for the court; [and]
(I) other conduct prohibited by obstruction of justice provisions under Title 18, United States Code ( e.g.
Federal courts, Congress, and federal agencies rely upon truthful information in order to make informed decisions. Federal law therefore proscribes providing the federal courts, Congress, or federal agencies with false information. The prohibition takes four forms: false statements; perjury in judicial proceedings; perjury in other contexts; and subornation of perjury.
Section 1001 of Title 18 of the United States Code, the general false statement statute, outlaws material false statements in matters within the jurisdiction of a federal agency or department. It reaches false statements in federal court and grand jury sessions as well as congressional hearings and administrative matters but not the statements of advocates or parties in court proceedings. Under Section 1001, a statement is a crime if it is false, regardless of whether it is made under oath.
In contrast, an oath is the hallmark of the three perjury statutes in Title 18. The oldest, Section 1621, condemns presenting material false statements under oath in federal official proceedings. Section 1623 of the same title prohibits presenting material false statements under oath in federal court proceedings, although it lacks some of Section 1621's traditional procedural features, such as a two-witness requirement. Subornation of perjury, barred in Section 1622, consists of inducing another to commit perjury. All four sections carry a penalty of imprisonment for not more than five years, although Section 1001 is punishable by imprisonment for not more than eight years when the offense involves terrorism or one of the various federal sex offenses. The same five-year maximum penalty attends the separate crime of conspiracy to commit any of the four substantive offenses.
A defendant's false statements in the course of a federal criminal investigation or prosecution may also result in an enhanced sentence under the U.S. Sentencing Guidelines for the offense that was the subject of the investigation or prosecution.
This report is available in abbreviated form—without footnotes, quotations, or citations—as CRS Report 98-807, False Statements and Perjury: A Sketch of Federal Criminal Law.