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- Curtis Painter, quarterback for the Indianapolis Colts
- John M. Palmer, politician (Democrat, Republican, Free Soil), Civil War General, Illinois State Senator, Illinois Governor
- Phoebe Palmer, evangelist and author
- Potter Palmer, real estate developer, businessman, founder of the Palmer House Hotel
- Danielle Panabaker, actress, Shark
- Kay Panabaker, actress, Summerland, Phil of the Future
- Jannero Pargo, point guard for the Memphis Grizzlies
- Anthony Parker, guard for the Cleveland Cavaliers
- Francis W. Parker, education reformer
- Mandy Patinkin, actor and singer, The Princess Bride, Dick Tracy, Chicago Hope
- Danica Patrick, auto racing driver
- Tom Paxton, (born 1937) folk musician and singer-songwriter
- Sean Payton, head coach for the New Orleans Saints
- John Mason Peck, Baptist minister and author
- Michael Peña, actor, World Trade Center, Crash, The Shield
- Jeff Perry, actor, Nash Bridges, Grey's Anatomy
- Pehr August Peterson, Rockford, Illinois industrialist and philanthropist
- William Petersen, actor, Gil Grissom on CSI: Crime Scene Investigation
- Father Michael Pfleger, controversial Roman Catholic priest
- Busy Philipps, actress, Dawson's Creek, Freaks and Geeks, ER
- Geoff Pierson, actor, Unhappily Ever After, Grace Under Fire, Dexter
- Tonya Pinkins, actress, All My Children, Enchanted
- John Podesta, White House Chief of Staff under Bill Clinton
- Fritz Pollard, first African American head coach in the NFL and Pro Football Hall of Famer
- Ernest Poole, Pulitzer Prize-winning novelist
- Michael Posner, Attorney, human rights advocate and Assistant Secretary of State under Barack Obama
- Joe Principe, musician, member of the band Rise Against
- Penny Pritzker, founder and current Chair of Classic Residence by Hyatt
- Richard Pryor, comedian and actor
- Kirby Puckett, Hall of Fame center fielder for the Minnesota Twins
- George M. Pullman, inventor and industrialist, founder of the Pullman Car Company
- David Purcey, relief pitcher for the Philadelphia Phillies
- Todd Purdum, national editor and political correspondent for Vanity Fair
Read more about this topic: List Of People From Illinois