In 1978, a joint congressional resolution established Asian/Pacific American Heritage Week. The first 10 days of May were chosen to coincide with two important milestones in Asian/Pacific American history: the arrival in the United States of the first Japanese immigrants (May 7, 1843) and contributions of Chinese workers to the building of the transcontinental railroad, completed May 10, 1869.

In 1992, Congress expanded the observance to a monthlong celebration.

Per a 1997 Office of Management and Budget directive, the Asian or Pacific Islander racial category was separated into two categories: one being Asian and the other Native Hawaiian and Other Pacific Islander.

The estimated number of U.S. residents of Asian descent, according to the 2010 Census, is 17.3 million. This group comprised 5.6 percent of the total population. This count includes those who said they were both Asian alone (14.7 million) and Asian in combination with one or more additional races (2.6 million).

California, with 5.6 million, is the state with the largest Asian population in the 2010 Census, followed by New York (1.6 million). Hawaii had the highest proportion of Asians (57 percent).

Chinese-Americans (3.8 million) were the largest Asian group, followed by Filipinos (3.4 million), Asian Indians (3.2 million), Vietnamese (1.7 million), Koreans (1.7 million) and Japanese (1.3 million). These estimates represent the number of people who reported a specific Asian group alone, and people who reported that Asian group in combination with one or more other Asian groups or races.