HELP! 31 ACT, Strong GPA, Where do I Apply!?

Based on selectivity alone, you will find lots of matches and realistic reaches (as well as some likely schools) in the ~40 to ~100 range in an analysis such as this: http://www.businessinsider.com/the-610-smartest-colleges-in-america-2015-9. For colleges of particular interest, I’d recommend you consider schools outside of this range as well. With respect to colleges with programs that generally match your academic interests, you might look into Vassar or Smith.