From the NG today, AP puts Illinois football at #51 all time. That is #12 in the current 14 teams and one point in the polls behind Northwestern.
http://www.news-gazette.com/sports/...2016-08-02/ap-illini-just-outside-top-50.html
These ranking were based on poll rankings over the last 80 seasons.
Ohio State took #1, in case you were wondering.
If your talking "all time," meaning all the way back to the 19th century, we're getting hosed a bit here, as the methodology in this survey doesn't favor us. They gave one point for every week a team appeared in the AP top 20 since 1936; two points for reaching no. 1; and ten points for winning an AP national championship. We won four "national championships"* between 1914 and 1927 that aren't counted, and our 1951 "national championship" was not awarded by the AP (Tennessee was their champion that year) so we got no credit for that either. Also, there were fewer total weeks to rank prior to the 1970s, when teams played 8-9 games a season without byes, which downplays our successes under Ray Eliot (although we weren't exactly AP top 25 mainstays during the Valek, Blackman, and Moeller eras, so perhaps that point is a wash). But even if you spotted us another 50 points in that survey, we'd still only get up to the low 40s. We were a powerhouse in the early 20th century and blipped on the radar here and there since but never really had one sustained, decade-long run in the modern polls that would have pushed us higher in a set of rankings like this.
* In quotation marks because "national championship" was a fairly subjective term in the 1910s and 1920s. In 1927, for example, we shared the national championship with four other teams, as there were ten different organizations awarding "national championships" that year. In our defense, we were the closest to a true national champion in 1927, winning five of the ten polls, including the Dickenson System poll, which was considered the most authoritative in that era.