This Presidential Primary coincides with a state/local primary. These coinciding primaries tend to have an impact upon voter turnout.

Participation in Illinois' delegate selection process is open to all voters who wish to participate as Democrats. Voters may register to vote up to 30 days preceding the Primary Election, and declare their affiliation by requesting a Democratic Primary Election ballot at the polls. Illinois does not require prior declarations of party affiliation as a pre-requisite to participating in the Primary Election.

Tuesday 15 March 2016 (presumably): Illinois Primary. Hours 6:00a-7:00p CDT (1100-0000 UTC). Delegate Pledging: Proportional Primary. Voter Eligibility: Open Primary.

Primary
Source: Illinois State Board of Elections.
Status: Official. Retrieved: Wednesday 20 April 2016.
Included in Nationwide vote.

Tuesday 15 March 2016 (presumably): 156 of 183 delegates to the Democratic National Convention are pledged to presidential contenders based on the results of the voting in today's Illinois Presidential Primary. A mandatory 15% threshold is required in order for a presidential contender to be pledged National Convention delegates at either the congressional district or statewide level. How the Democratic Proportional Delegate Allocation Math works.

• 102 district delegates are to be pledged proportionally to presidential contenders based on the primary results in each congressional district.
• 54 delegates are to be pledged to presidential contenders based on the primary vote statewide.
  • 34 at-large National Convention delegates
  • 20 Pledged PLEOs

Primary
Source: Illinois State Board of Elections.
Status: Official. Retrieved: Wednesday 20 April 2016.

See 2016 Democratic National Convention from the Democratic Party of Illinois.

National Convention District level delegates appear on the primary ballot. Delegate candidates must file nominating petitions, a Statement of Candidacy, and a Presidential Preference form with Illinois State Board of Elections. Presidential candidates are given the opportunity to remove any of their delegate candidates prior to date the Illinois State Board of Elections certifies the Primary ballot. The Delegates are selected from the highest vote-getters.

Monday 9 May 2016 (presumably): National Convention delegation meeting.

National Convention Pledged PLEO and At-Large delegates are elected at State Party headquarters by a quorum of the district-level delegates according the the results of the primary.

The remaining 27 National Convention delegates consist of

• 27 Unpledged PLEO delegates:
• 15 Democratic National Committee members.
• 11 Members of Congress (1 Senator and 10 Representatives).
• 0 Governors.
• 1 Distinguished Party Leader: President Barack Hussein Obama.

These 27 delegates and will go to the Democratic National Convention officially "Unpledged".

State Representative Scott Drury (Democratic) introduced HB 193 on 14 January 2015. This bill would move the Presidential and the partisan primaries from the 3rd Tuesday in March to the 4th Tuesday in June.

HB 3107, introduced by state Representative. Steven Andersson (Republican) on 24 February 2015, would move the Presidential and the partisan primaries from the 3rd Tuesday in March to the 3rd Tuesday in July.