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

Mitt Romney received 1,152,460 (59%) votes, beating Barack Obama who gained 808,496 (41%) by 343,964 votes in Louisiana.

Mitt Romney won 54 counties whereas Barack Obama won 10 counties in the total of the 64 counties in the State of Louisiana.

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 Louisiana, his 808,496 gained votes represents 1.3% of his popular vote victory. The remaining 49 states contributed to the remaining 98.7% 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 (East Baton Rouge, Jefferson, Orleans), it is still possible for other candidates to catch up, given the amount of large counties of similar size.

Top 15 Counties Comparison in Primary Elections vs General Elections

General Elections
Barack Obama

General Elections
Mitt Romney

East Baton Rouge and Orleans, two of the larger counties, voted in favor of Barack Obama giving him a 108k vote advantage. Jefferson, another larger county voted in favor of Mitt Romney giving him a 32k voter advantage in that county. However, Romney's steady win in the less dense counties was enough to overcome that deficit, making him gain an upper hand in the State of Louisiana.

Related References: 2016 Louisiana Primary Election Story, 2016 Louisiana General Election Story, 2020 Louisiana Primary Election Story, 2020 Louisiana General Election Story