Donald Trump won a landslide victory during Tuesday's California Republican primary, but still earned a lower percentage of votes than Mitt Romney did in 2012.

Only registered Republicans could vote in the Republican presidential primary. Trump earned 75 percent of the votes counted as of Friday. Romney earned 80 percent in 2012, with former U.S. Rep. Ron Paul siphoning off much of the rest.

All of Trump's major opponents had suspended their campaigns well before California's primary. So the fact they still received hundreds of thousands of votes could be viewed as a sign of disunity.

Trump got his strongest support among Republican voters in rural, northern parts of the state, including Colusa, Lassen, Modoc and Tehama counties. (Many of the same places supported Bernie Sanders over Hillary Clinton in the Democratic primary.)

Trump did not do as well among Republicans in several urban parts of the state, particularly around San Francisco and Los Angeles.

This map shows, by county, the areas where Trump received the highest and lowest proportion of Republican votes in the presidential primary.

Source: California Secretary of State