Adeline Jay Geo-Karis (March 29, 1918 – February 10, 2008) was a Republican politician and a member of the Illinois Senate for the 31st District, where she served for over 25 years. Prior to her election as Senator, she was in the Illinois House of Representatives from 1973 to 1979. Known simply as "Geo" to her constituents, she was a popular politician in Lake County, Illinois for many years. Known for her no-nonsense attitude and her ability to work across party lines, she also served for a time as Mayor of Zion.