Ohio Gov. Mike DeWine tested positive for COVID-19 on Thursday, his office said.
Mr. DeWine took a test as part of a standard protocol to greet President Trump at an airport in Cleveland.
Mr. DeWine, a Republican, is asymptomatic and plans to quarantine at his home in Cedarville for two weeks.
Lt. Gov. Jon Husted, who also plans to greet the president, tested negative.
Mr. DeWine is the second governor known to have tested positive for the coronavirus after Oklahoma Gov. Kevin Stitt, a Republican, announced a positive test last month.