There is a lot that’s been written about how the male-female ratios (note that these stats don’t necessarily speak to gender and also doesn’t equate to sexual orientation) can significantly impact heterosexual dating culture on campuses.
Apparently, on campuses where there are significantly larger numbers of women than men, hook-up culture is dominant vs. campuses where there are larger numbers of men on which there tends to be more coupling/long-term relationships.
Your daughters were fortunate to find boyfriends with similar interest in being part of a couple, etc - that may be separate and apart from the general dating culture, however.
As others noted, there are more women than men at most colleges and that’s also written about a lot. In one article I read, they showed a table looking at enrollment historically. The last time there weren’t more female college students than male is in the late 1970s.
In terms of schools where there are more men, yes to military institutes but also in the engineering and science centric schools. CalTech is a good example, but so is far less prestigious Wentworth Institute of Technology in Boston.
Partial list of schools w/high percentages of male-to-female students:
MIT
Caltech
Purdue University (main campus)
Georgia Tech
Berklee School of Music
Juilliard School
Bentley University
Cooper Union for the Advancement of Science and Arts
Rensselaer Polytechnic Institute
Rochester Institute of Technology
Worcester Polytechnic Institute
Illinois Institute of Technology
Wentworth Institute of Technology
New Mexico Institute of Mining and Technology
Colorado School of Mines
Rose-Hulman Institute of Technology
Pennsylvania State University - Wilkes Barre
Missouri University of Science & Technology
Florida Institute of Technology
New York Institute of Technology
Milwaukee School of Engineering
University of Chicago
Rice University
University of Notre Dame
University of Illinois, Urbana-Champaign
UC Santa Cruz
Pennsylvania State University
Virginia Tech
Case Western Reserve University
Texas A&M University, College Park
University of Texas at Dallas
Oregon State University
University of Maryland, College Park
California Polytechnic University - San Luis Obispo
Drexel University
Clemson University
Texas Tech
University of Utah
University of Maine
University of Nebraska, Lincoln
Southern Illinois University, Carbondale
Iowa State University of Science and Technology
Kansas State University
University of Colorado, Boulder
Oregon Institute of Technology
Even numbers
Yale University
Princeton University
Ohio State University
University of Michigan, Ann Arbor
University of California, San Diego
Arizona State University
Carnegie Mellon
Santa Clara University
Almost even numbers
Columbia University
Dartmouth University
Harvard University
Stanford University
Northeastern University
That said, my understanding is that there can be problems for women at these kinds of schools - sexist attitudes that they constantly need to push against that’s less of a thing at say a liberal arts school.
Plus, I always keep in mind that the ratio says nothing about availability. A friend who attended Carnegie Mellon let me know that in his opinion many of his fellow guy classmates weren’t actually “dateable.” And I’m also aware that some portion of the men at a school will not opt into dating at all for cultural or religious reasons and have other means of finding a partner.