Some of this may have already been posted to various threads, but I thought that I would post it all in one spot anyway… My apologies for any redundancies
Common Fact Sheet containing what UW considers very important/important/etc in the admissions process, admissions requirements (i.e., how many math classes), average GPA, middle 50% ACT scores etc. Basically, the data that is posted at collegedata, Princeton review, etc., but from the official UW website
https://apir.wisc.edu/publisherssurvey/CDS_2014-2015.pdf
Admission statistics including in-state, MN, out-of-state (excluding MN), and international admission rates (I am pretty sure @Madison85 posted this elsewhere)
https://apir.wisc.edu/admissions/New_Freshmen_Applicants.pdf
Fast Facts about UW, which is the data one typically finds on the overview pages of US News & World report, etc
https://apir.wisc.edu/fastfacts.htm
Data Digest which has detailed data on enrollment, alumni, faculty, and research funding
https://apir.wisc.edu/datadigest/201415Digest/dd15_web.pdf
I have relied on information from US News and collegedata, but it is probably better to go directly to the source (i.e., these official UW websites)