A head to head comparison of the North Carolina 2012 General Election gives us an idea of the break down of the voters.    

Mitt Romney received 2,275,850 (51%) votes, beating Barack Obama who gained 2,178,390 (49%) by 97,460 votes in North Carolina.

Mitt Romney won 70 counties whereas Barack Obama won 30 counties in the total of the 100 counties in the State of North Carolina.

Presidential General Elections

During the 2012 General elections, over 122M total number of votes were cast. Barack Obama got 62,614,654 (62.6 Million) over Mitt Romney's 59,141,654 (59.1 Million). He won the popular vote by 3,472,979 (3.4 Million). Even though he lost to Mitt Romney in the State of New York, his 2,178,390 gained votes represent 3.4% of his popular vote victory. The remaining 49 states contributed to the remaining 96.6% popular votes victory.

Top 15 Counties in Primary Elections vs General Elections

All Candidates (General Elections)

These 15 counties play an important role in these Primary elections. If a candidate, can get a sizable majority in the larger counties (Wake, Mecklenburg, Guilford), it becomes very difficult to win majorities in the smaller counties without voter outreach and increased voter participation in them.

Top 15 Counties Comparison in Primary Elections vs General Elections

General Elections
Barack Obama

General Elections
Mitt Romney

Wake, Mecklenburg and Guilford, three of the larger counties, voted in favor of Barack Obama giving him a 195k vote advantage. However, Mitt Romney's steady win in the less dense counties (like New Hanover, Cabarrus, Union and more) was enough to overcome that deficit, making him gain an upper hand in the State of North Carolina.

Related References: 2016 North Carolina Primary Election Story, 2016 North Carolina General Election Story, 2020 North Carolina Primary Election Story, 2020 North Carolina General Election Story