In 1775 the Spanish sent an expedition from San Blas near the entrance to the Gulf of California to explore the northwest coastline to latitude 65°N as an expression of their right to the western coasts of North America.
     Don Juan Francisco de la Bodega y Quadra and his pilot, Antonio Maurelle, who were a part of the expedition got as far north as latitude 58° before they were forced to turn back. In 1779 Bodega and Maurelle sailed from San Blas and proceeded to Prince William Sound, where again they had to turn back because of sickness.
     Bodega became superintendent of the marine department at San Blas, and in 1791 he composed the map Carta General de quanto asta hoy se ha descubierto y examinado por los Españoles en la Costa Septemtional (sic) de California (A General Map of how far the Spaniards have now discovered and explored in the northern coast of California). On this map he plotted the western coastline from Acapulco to Isla de Serantes.
     The map on which the stamp is based is Bodega’s manuscript map which is in the Department of Hydrography at Madrid, Spain. The stamp was issued to honor the explorers of the Northwest coast of North America.