The National Institute of Mental Health website has great resources to learn more about health topics. Here you can learn about general mental health, specific disorders, access factsheets and statistics, and read about current research.
The Centers for Disease Control and Prevention website mental health allows you to learn about mental health, read data and publications, and access more tools and resources.
The American College Health Association website has a page dedicated to mental health educational resources. These resources cover various topics involving mental health and many are specific to college students.
This fact sheet by the National Alliance on Mental Illness gives a great overview on mental health stats in the US. You can access more factsheets and data by NAMI on different mental health topics here on their Mental Health by the Numbers website.