Here are some popular online archival resources you can access.
Digitized Newspapers through the Illinois Digital Newspaper Collection
UI Histories Project created by Kalev Lettaru
History about the founding, buildings on campus, gifts/memorials, collections, student life, milestones, board of trustees, special collections, and a digital library!
http://uihistories.library.illinois.edu/cgi-bin/cview?SITEID=1&ID=1
Digital Content/University Historical Images
http://www.library.illinois.edu/archives/archon/index.php?p=digitallibrary/digitallibrary
Dig-Libsysdigi Electronic Records Repository
http://www.library.illinois.edu/archives/archon/index.php?p=core/search&locationid=33
Pocket Facts: 1990-2003
Pocket Facts is produced by the Office of University Relations, and data are provided by the Office for Planning and Budgeting. Both offices are units of University Administration.
https://www.uillinois.edu/cms/One.aspx?portalId=1324&pageId=136773
http://www.library.illinois.edu/archives/guides/disability/digital/index.php
Oral Histories Project at the Student Life and Culture Archival Program
http://archives.library.illinois.edu/slc/oral-history-portal/
Board of Trustees Minutes
http://uihistories.library.illinois.edu/cgi-bin/rview_search?mode=search&REPOSID=8&DOCTYPE_BOT=on
Board of Trustees Members
https://www.bot.uillinois.edu/resources/historical/historical_leadership
Digitized Illio Yearbooks 1970-1989
http://archives.library.illinois.edu/archon/?p=digitallibrary/digitalcontent&id=4412
Student Life and Culture Digital Resources
https://www.library.illinois.edu/slc/digital-resources/
Primary Source Tutorial
A guide to how to examine and interpret primary source materials.
http://www.library.illinois.edu/village/primarysource/index.htm