Loyalty Day is observed on May 1 in the United States. It is a day set aside for the reaffirmation of loyalty to the United States and for the recognition of the heritage of American freedom.

The holiday was first observed in 1921, during the First Red Scare. It was originally called “Americanization Day,“ and it was intended to replace the May 1 (“May Day”) celebration of the International Workers’ Day, which commemorates the 1886 Haymarket affair in Chicago.

During the Second Red Scare, it was recognized by the U.S. Congress on April 27, 1955, and made an official reoccurring holiday on July 18, 1958 (Public Law 85-529). President Dwight D. Eisenhower proclaimed May 1, 1955, the first observance of Loyalty Day. In 1958, Eisenhower urged Congress to move Child Health Day to the First Monday in October, to avoid conflicting with Loyalty Day. Loyalty Day has been recognized with an official proclamation every year by every president since its inception as a legal holiday in 1958.

Loyalty Day is defined as follows in 36 U.S.C. § 115:

(a) Designation.— May 1 is Loyalty Day.
(b) Purpose.— Loyalty Day is a special day for the reaffirmation of loyalty to the United States and for the recognition of the heritage of American freedom.
(c) Proclamation.— The President is requested to issue a
proclamation—(1) calling on United States Government
officials to display the flag of the United States on all
Government buildings on Loyalty Day; and (2) inviting the
people of the United States to observe Loyalty Day with
appropriate ceremonies in schools and other suitable
places. (Source: Wikipedia)