I will be a senior in high school this year and am planning on majoring in econ and minor in Chinese. What schools would be best for these areas of study?
Hamilton, Williams, or Middlebury would be phenomenal for those interests:
https://www.chinainsight.info/education/general/231-associated-colleges-in-china-a-hidden-gem.html
@dog423451, Most colleges have very good econ departments and excellent study abroad programs in China
E.g., Vassar
https://internationalprograms.vassar.edu/programs/exchange/
https://internationalprograms.vassar.edu/programs/approved/east-asia/
Wesleyan has an outstanding econ dept and also offers a number of excellent programs in China, including C.V. Starr - Middlebury School in China.
http://www.wesleyan.edu/cgs/osa/programs/asia.html
You should narrow your college search to location, size, etc.
@dog423451 : what are your stats? Where do you live?
@dog423451, Something else to consider is how many study in China programs are offered. It appears that Hamilton offers only one per approved program and you’re required to pledge to speak only Chinese. Most schools offer a number of programs without a requirement to speak only Chinese. https://www.hamilton.edu/academics/offcampusstudy/preapproved-programs
A good example of program diversity are those at Smith. Many colleges, including Smith, Vassar, etc, offer the ACC program mentioned in post # 1.
https://www.smith.edu/studyabroad/approved_asia.php
Do your due diligence.
Hamilton of course approves only one program in China because it’s the rigorous program they administer.
For some reason, as with other colleges, Hamilton does not have a number of per approved programs.
My point was that administering only one program and not per approving additional programs offered through various colleges/organizations is extremely limiting. It’s nice to have choices. 
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Are there any bigger schools than Hamilton that would still be very good in both these areas?
Well, you could attend HKU or HKUST or some such as an international student. Their list prices are considerably lower than those of many US universities. You may want to investigate if their academic offerings are suitable (both appear to have a more pre-professional “business” leaning). Note, however, that if you want to practice Chinese language skills in the local community, Hong Kong is heavily Cantonese (as opposed to Mandarin) speaking.
Yale, Columbia, Cornell, Stanford.
Depending on your state of residency, your state universities may have good economics and Chinese departments.
It may help others help you if you specify your state of residency and your cost constraints. Also, if you have Chinese language skill that would place you in a Chinese language course more advanced than the beginner course.
I live in NJ and have taken Chinese every year of high school (the past two years were honors). my GPA is a 4.03 (4.0 weighted scale) and I got a 31 on the ACT (33 Superscored).
Rutgers offers Chinese language courses up to 8th semester level (with different lower level tracks for non-heritage and heritage speakers) and a Beijing summer program.
Rutgers also has an extensive offering of economics courses.
Oberlin
The University of Chicago has strong programs in both. So do most of the Ivies and Stanford.
However, admission to these schools is very selective and sticker prices are very high.
If any of these colleges interest you and you want to take a chance on admission, run their online net price calculators. Ask your parents if they are able and willing to cover the Expected Family Contributions.
Are any other factors important to you besides academic program strengths?
Rutgers may be a good choice. Many other state universities could meet your academic needs (if your family can afford the $35K-$55K OOS sticker prices.)
If you want more personal attention and need-based aid, then the top ~40 liberal arts colleges might be worth considering. Middlebury, Wesleyan, and Oberlin are all larger than Hamilton (and a bit less selective than the Ivies, Stanford, or UChicago). If they aren’t large enough for you, consider Georgetown, USC, Tufts, Notre Dame. Wake Forest is a little smaller and a bit less selective than those 4.
Right now, you should try to identify match and safety schools that offer an appropriate level of Chinese (most colleges will offer economics). UVA, Wake Forest, or Wesleyan would be good high matches for you for instance - very different atmospheres though.
Look into TCNJ v. Rutgers, both honors (apply to both).
What’s your parents’ budget? Many state flagships with strong economics also offer Chinese through a good level, the big difference would be Honors College and cost (as some may offer merit scholarships of various amounts).
I’m not sure how Middlebury hasn’t been listed as the top choice on everyone’s list here. When it comes to languages, Middlebury is the benchmark school. They also happen to have one of the top Economics programs in the country.
An ACT 31 or superscored 33 is a bit stretch for Middlebury, but you can try
Wake is test optional, more likely, so are Oberlin, Wesleyan, UVA if full pay, TCNJ and Rutgers.