A more learned man has weighed in on the question posed in February regarding The Philippines. Previous laws and several constitutions are quoted in Manuel L. Quezon III's "The Philippines are or is?" It looks like the earliest official reference to the Philippines may be found in the Jones Law of 1916:
Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That the provisions of this Act and the name "The Philippines" as used in this Act shall apply to and include the Philippine Islands ceded to the United States Government by the treaty of peace concluded between the United States and Spain on the eleventh day of April, eighteen hundred and ninety-nine, the boundaries of which are set forth in Article III of said treaty, together with those islands embraced in the treaty between Spain and the United States concluded at Washington on the seventh day of November, nineteen hundred.
