Bryn Mawr: (in person and online options)
https://www.giftedstudy.org/day/brynmawr/
Northwestern (online):
https://www.ctd.northwestern.edu/program_type/summer-programs
Johns Hopkins:
https://cty.jhu.edu/summer/index.html
Hoagies:
https://www.hoagiesgifted.org/summer.htm
William and Mary:
https://education.wm.edu/centers/cfge/precollegiate/sep/sep-brochure-2019-summer1.pdf
Franklin Institute:
https://www.fi.edu/summer-camp