Easy as in, easy to get accepted into? Or just colleges which don't make it difficult to double major?
I only ask because most colleges will let you double major so it really depends on the type of school you are looking for. And since most colleges will let you double major you could basically just look into what are the easiest colleges to be accepted into, but I'm sure that's not what you're looking for. It's also going to depend on what you want to double major in, some may be easier than others.
Brown is one, they have an open curriculum. Actually, here's a list of schools with open curriculums which you might want to investigate: https://blog.collegevine.com/open-curriculum-schools-11-colleges-that-allow-students-to-direct-their-own-learning/. Double majoring in one of those schools might be easy.
University of Southern California is another good choice - I think they even have a scholarship specifically for people double majoring. Northwestern might be another good option. And there are plenty of schools which offer built-in double majors for specific subjects. Some are: Northeastern, UPenn, Bentley, University of San Diego, University of Maryland, Claremont McKenna, Carnegie Mellon University, Drexel, BU, and Westfield State.
If you let me know what you're interested in majoring in I could probably find more options since many of the schools listed might not be interesting to you/might not offer a double major in what you are interested in pursuing.
To keep this community safe and supportive:
Easy as in they allow me to double major :) I've read that Princeton and MIT don't really let you for example