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

Tuesday 15 March 2016: Ohio Primary. Hours 6:30a-7:30p EDT (1030-2330 UTC). Delegate Pledging: Proportional Primary. Voter Eligibility: Modified Primary.

Primary
Source: Ohio Secretary of State.
Status: Official. Retrieved: Wednesday 20 April 2016.
Included in Nationwide vote.

Tuesday 15 March 2016: 143 of 160 delegates to the Democratic National Convention are pledged to presidential contenders based on the results of the voting in today's Ohio Presidential Primary. A mandatory 15 percent 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.

• 93 district delegates are to be pledged proportionally to presidential contenders based on the primary results in each of the State's 16 congressional districts.
• In addition, 50 delegates are to be pledged to presidential contenders based on the primary vote statewide.
  • 31 at-large National Convention delegates
  • 19 Pledged PLEOs

District-level delegates are slated to each Presidential Preference in pre-primary caucuses held in each Congressional District on 5 January 2016 at 7:00 PM EST.

Primary
Source: Ohio Secretary of State.
Status: Official. Retrieved: Wednesday 18 May 2016.

Ohio Democratic Party Announces Final List of District-Level Delegates for Democratic National Convention.

Saturday 16 April 2016: Post Primary Caucus. Delegates are elected according to the results of the primary. There is one caucus location per congressional district.

If a presidential candidate has qualified to receive delegates but has failed to slate a sufficient number of delegates, then additional delegates for that candidate will be selected during the post-primary caucus.

Saturday 14 May 2016: State Executive Committee

National Convention Pledged PLEO and At-Large Delegates are selected by the State Democratic Executive Committee according to the results of the primary.

The remaining 17 National Convention delegates consist of

• 17 Unpledged PLEO delegates:
• 11 Democratic National Committee members.
• 5 Members of Congress (1 Senator and 4 Representatives).
• 0 Governors.
• 1 Distinguished Party Leader (former DNC Chairman David Wilhelm)

These 17 delegates and will go to the Democratic National Convention officially "Unpledged".

HB 153, introduced by Representative Mike Dovilla (Republican) on 13 April 2015 and signed by Governor John Richard Kasich (Republican) on 10 June 2015, moves the Presidential Primary from the 1st Tuesday after the 1st Monday in March to the 2nd Tuesday after the 1st Monday in March.