Asian Pacific American Heritage Month (APAHM) is celebrated in May to commemorate the contributions of people of Asian and Pacific Islander descent in the United States. Congress passed a joint Congressional Resolution in 1978 to commemorate Asian American Heritage Week during the first week of May. This date was chosen because two important anniversaries occurred during this time: the arrival of the first Japanese immigrants in America on May 7, 1843 and the completion of the transcontinental railroad (by many Chinese laborers) on May 10, 1869. Congress later voted to expand it from a week long to a month long celebration.