The document discusses Spain's settlements in North America called the Spanish borderlands. Spain's main interests were protecting its empire, expanding its economy, and converting Native Americans to Catholicism. The Spanish established settlements like presidios and missions to raise livestock, build irrigation canals, explore waterways, and protect claims from other European countries while also converting Native Americans to their faith. The Spanish borderlands north of New Spain served as a buffer zone to protect its colonies from attacks and encroachment from other European powers like France and England.