Only Voters registered as Republican are eligible to participate.

Tuesday 8 March 2016: Idaho Primary. Hours 8:00a-8:00p MST (1500-0300 UTC) / 8:00a-8:00p PST (1600-0400 UTC). Local option allows polling places to open at 7 AM. A sizable part of IDAHO is in PT but, as the MT section is the much more populated portion of the state, the networks consider that "most of the polls in IDAHO" are closed by 8 PM MT. Delegate Selection: Winner-Take-Most Primary. Voter Eligibility: Closed Primary.

Primary
Source: Idaho Secretary of State.
Status: Official. Retrieved: Tuesday 2 August 2016.
Included in Nationwide vote.

Tuesday 8 March 2016: All 32 of Idaho's National Convention delegates are pledged to Presidential contenders based on the vote in today's Presidential Primary.

• If one candidate wins more than 50% of the statewide vote, that candidate receives all the National Convention Delegates. [Idaho Republican Party State Rules. Idaho Rules for Selection of Delegates to the National Convention and State Convention. Article VI. Section 3.(a)]
• Otherwise, if at least 1 candidate receives 20% or more of the statewide vote, the National Conventions delegates are allocated proportionally to those candidates receiving 20% or more of the statewide vote. [Idaho Republican Party State Rules. Idaho Rules for Selection of Delegates to the National Convention and State Convention. Article VI. Section 3.(b)]
• Otherwise, National Conventions delegates are allocated proportionally. [Idaho Republican Party State Rules. Idaho Rules for Selection of Delegates to the National Convention and State Convention. Article VI. Section 3.(b)]

A NOTE re: Rounding: All rounding will be done to the nearest whole number. Any rounding and/or over/under allocated delegates will be handled by the Nominating Committee.

Primary
Source: Idaho Secretary of State.
Status: Official. Retrieved: Tuesday 2 August 2016.

Statewide proportional for candidates receiving 20% or more of the vote.
Cruz: 32 delegates × 100,889 ÷ 163,302 = 19.770 delegates. Round to 20.
Trump: 32 delegates × 62,413 ÷ 163,302 = 12.230 delegates. Round to 12.

Tuesday 17 May 2016: Idaho Precinct Conventions.

Friday 20 May - Saturday 28 May 2016 (presumably): Idaho County Conventions.

Thursday 2 June - Saturday 4 June 2016 (presumably): The Idaho State Republican Convention convenes.

No later than 30 days before the State Convention, each Presidential candidate prepares a list of proposed National Convention delegates. National Convention delegates are elected according to the results of the primary.

... Delegates ... shall be obliged on the first ballot taken at the Republican National Convention to vote for the candidate who nominated them, provided any Delegates selected as representing the "uncommitted" choice shall be free to cast their vote for any candidate whose name has been placed in nomination before the Republican National Convention. In the event of death or withdrawal ... or release of Delegates by a candidate prior to the first ballot ... Delegates committed to such a candidate ... become uncommitted [Rule Article VI Sections 8 & 9].

SB 1049, introduced on 6 February 2015 by the State Affairs Committee, would create a Presidential Primary on the 2nd Tuesday in March (8 March 2016). The state's Presidential Primary was previously repealed in 2012.

SB 1066, introduced on 12 February 2015 by the State Affairs Committee, would create a Presidential Primary on the 2nd Tuesday in March (8 March 2016). This bill is similar to SB1049 but provides details on whether or not non-party members can participate in another Party's primary. The bill was signed into law by Governor Butch Otter (Republican) on Thursday, 9 April 2015.

9 February 2015: NPG of Idaho reports that the Central Committee of the Idaho Republican Party recently voted to select their Presidential delegates by primary rather than caucus should the state Legislature approve the 8 March 2016 primary.