Final answer:
St. Augustine, founded in 1565 by Pedro Menéndez de Avilés, is the oldest continuously-settled European settlement in the continental United States.
Step-by-step explanation:
The first Spanish settlement founded in 1565 in what is now the United States was St. Augustine. This settlement was established by Pedro Menéndez de Avilés and is notable for being the oldest continuously-settled European settlement in the continental United States.
St. Augustine was founded following the displacement of the Timucua Natives and proved successful due to the Spaniards' cultivated relationship with the indigenous people despite earlier failed attempts at establishing other settlements in Florida.