However, Sen. Ted Cruz of Texas is coming off a particularly strong "Super Saturday" performance, including double-digit wins in Kansas and Maine, a delegate tie in Louisiana with Trump and a respectable showing in Kentucky. More and more, it's starting to look like Cruz is the non-Trump candidate poised to give the billionaire businessman a run for his money heading into the Republican National Convention this summer.

The Cruz campaign has raised $54.6 million since the start of the election cycle, according to filings to the Federal Election Commission. With the exception of retired neurosurgon Ben Carson – who spent enormously on direct mail campaigns and marketing rather than field operation and staff – that's more money than the rest of the Republican field. Cruz and Trump are considered outsider candidates by the Republican establishment, though the key difference is that while Trump's campaign is largely rooted in free media and name recognition, Cruz has arguably the strongest ground game of any candidate on the Republican side this cycle.

U.S. News analyzed contribution data by ZIP code for Republican candidates Trump, Cruz and Sen. Marco Rubio of Florida, and for Democratic candidates Hillary Clinton and Sen. Bernie Sanders of Vermont. Here are the ZIP codes that supported Cruz above the other candidates analyzed. (See the full analysis and methodology here.)

