This is taken from the St. Croix this Week website describing what VI/Puero Rican Friendship Day stands for:
Puerto Ricans have been part of this community from the beginning of the last century and have become a strong, powerful group of people working hard to improve themselves, their families and what became their new home, St. Croizx.
Their influence was recognized in 1964 by the local Legislature, under Governor Ralph E. Paiewonsky, approving Act No. 1075 making a historical change. Columbus Day, observed in all the Americas as the Discovery Day, was now to be Virgin Islands and Puerto Rico Friendship Day. This bill called upon the citizens of the Virgin Islands to "observe the occasion with fitting ceremonies honoring Puerto Ricans residing in our midst and who have made substantial contributions to the advancement and progress of the Virgin Islands."
We enjoyed a day at Carambola and observed friendship with our family ;)