TAKE a glimpse at a political map of America, and you could be forgiven for thinking that its 50 states divide neatly into one of two partisan camps: red (Republican) and blue (Democratic). In recent decades, these maps have been highly consistent from one presidential election to the next: since 1996, 35 states have voted for the same party without fail. This year’s presidential candidates are actively campaigning in just a dozen “swing” states, leaving the bulk of the electorate seemingly redundant.

But as our county map above demonstrates, state-level data mask considerable local-level variation in America’s political divisions. Take Mississippi, which hasn’t voted for a Democratic candidate for 40 years. In 2012, 31 of the state’s 82 counties voted for Barack Obama. However, the fierce partisan loyalty of the Magnolia State’s Republican counties—they voted 65-35 in favour of Mitt Romney—is expected to ensure that Mississippi remains red this year, despite Donald Trump’s unpopularity.

At times, observing county-level election data can be as distorting as it is illuminating. In New York, which hasn’t given its electoral-college votes to a Republican since Ronald Reagan’s sweeping victory in 1984, 26 of the state’s 52 counties voted for Mitt Romney in 2012. But their sparse population means that New York appears redder than it is: those Republican counties contain less than 10% of its population.

In 2012, more votes were cast for Democratic candidates in the House of Representatives than Republican ones. Yet the GOP still won a comfortable majority in the chamber, because its voters were spread out more evenly across congressional districts. By similar logic, given the party’s increasingly rural base, the Republicans would have a stranglehold on the presidency if it were fought on a county-by-county rather than state-by-state basis. Over the past 60 years, Republican presidents have bagged 2,390 counties on average before making it to the White House, whereas their Democratic counterparts have won just 1,412. In 2012, Democrats won just 712 counties, the lowest of any presidential victory in modern history.