DOVER — Delaware’s Republican Party chairman is urging the GOP’s three presidential candidates to visit the First State ahead of next month’s primary contest.

With Donald Trump of New York, U.S. Sen. Ted Cruz of Texas and Ohio Gov. John Kasich competing in a process that might not be decided by the time the national party gathers for the July nominating convention in Cleveland, Delaware’s April 26 primary could be important, despite its late occurrence.

Charlie Copeland

“I have said for months that Delaware’s presidential primary will be relevant in 2016, and I expect each of the candidates to spend time with First State Republicans asking for their vote,” Charlie Copeland said in a statement.

Mr. Trump currently holds the lead in the delegate count, with Sen. Cruz second.

Delaware’s primary takes place the same day as primaries in Pennsylvania, Maryland, Connecticut and Rhode Island.

The state’s 16 delegates are pledged to support the primary winner at the national convention, although they can change their vote if the process goes beyond a first ballot.

“Every delegate is going to count as we move closer to Cleveland,” Mr. Copeland said. “Any candidate who wants the support of Delaware’s delegates needs to win the primary, and the only way to accomplish that is to visit the state and directly ask for support.”

Delaware’s primary is closed, meaning Republicans can vote only for Republicans and Democrats can back only Democratic candidates.

The 16 delegates will be selected at the Delaware GOP’s convention April 29 and 30.

Prior presidential candidates who have visited Delaware in recent years while campaigning include Barack Obama, Newt Gingrich and Mitt Romney.