Possible Clues:

• Spanish noblewoman ___ de Castro
• Juana ___ de la Cruz, Mexican poet/nun
• Spanish Agnes
• Agnes, in Spain
• Agnes, in Argentina
• Doña __, volcano in northern Chile
• Name that anagrams to a trig ratio
• Trésor spokesmodel Sastre
• Mission Santa ___ (National Historic Landmark in California)
• Woman's name that's also a plural suffix