May is Asian Pacific American (APA) Heritage Month—a celebration of Asian and Pacific Islanders in the United States. In June 1977, Representatives Frank Horton of New York and Norman Y. Mineta of California introduced a House resolution that called upon the president to proclaim the first ten days of May as Asian/Pacific Heritage Week. The following month, senators Daniel Inouye and Spark Matsunaga introduced a similar bill in the Senate. Both were passed. On October 5, 1978, President Jimmy Carter signed a Joint Resolution designating the annual celebration.
In May 1990, the holiday was expanded further when President George H. W. Bush designated May to be Asian Pacific American Heritage Month. May was chosen to commemorate the immigration of the first Japanese to the United States on May 7, 1843, and to mark the anniversary of the completion of the transcontinental railroad on May 10, 1869. The majority of the workers who laid the tracks were Chinese immigrants.
Below are some related links:
APA Heritage Month-Infoplease.com
Library of Congress APA Heritage Month website
The Early Chinese Canadians 1858-1947
Asian Reflections on the American Landscape
Japanese American Archival Collection-image base