U.S. long-term treasury bonds refer to bonds issued by the U.S. government with a maturity of more than 10 years.

The term of American long-term national debt generally refers to the maturity date of the bond, that is, how many years after the bond is issued, the principal and interest will be repaid.

For example, if the US government issues long-term treasury bonds with a term of 30 years, then the term of such bonds is 30 years. This means that within 30 years after the issuance of bonds, the government is obliged to repay the principal and interest of bonds in the agreed way.

The term of long-term US Treasury bonds is generally more than 10 years, including 10-year bonds, 20-year bonds and 30-year bonds. The yield of these bonds is usually higher, because investors have to bear a long interest expense risk during holding bonds.