Clinton's nearest rival Bernie Sanders has 32 per cent, while Marco Rubio trailed Trump with 28 per cent.
Trump's win proved a fatal blow to Rubio's campaign. The Republican senator, who was born and grew up in Florida, has suspended his bid for the nomination.
Clinton won Ohio with a 66 per cent lead in the state, and in the Republican race John Kasich won with 43 per cent versus Trump's 34 per cent.
Voters from Florida, Illinois, Missouri, North Carolina and Ohio took to the polls during so-called Super Tuesday.
Clinton led North Carolina with 59 per cent, against Sanders' 38 per cent. At the time of writing, Trump was in the lead in North Carolina too, according to reports, with 42 per cent, while Cruz in second place has 33 per cent.