As the amount of Spanish-speaking Americans is increasing, do some towns, counties, or states mandate all public school students to learn at least some Spanish?
Many states like New York and Texas require some study of a language other than English. They don't specify that this should be Spanish, but Spanish is by far the most common. California requires either a foreign language or visual/performing arts. In all cases, these requirements are limited to a year or two at most.
As mentioned in the comments on the question, public school students in Puerto Rico are obviously required to learn Spanish as it is the primary language of instruction there. English is also a required subject at all levels.