Gerald Herbert / AP Photo - Eric Gay / AP Photo

Not so fast. When it comes to delegates, it turns out Mitt Romney did not win Michigan.

ABC News projects that the 30 delegates awarded based on Michigan's  Tuesday primary will be evenly split - 15 delegates for Mitt Romney and 15 delegates for Rick Santorum.

Mitt Romney may have won the overall vote by a margin of 3 points , but Michigan awards it's delegates based on how the candidates did in each of the state's 14 congressional districts, not solely on the popular vote totals.

The system works like this: the winner of each Congressional district gets two delegates. Two additional delegates are awarded based on the overall statewide vote - one delegate for the first place winner and one delegate for the second place winner if he gets more than 15 percent of the popular vote.

Rick Santorum and Mitt Romney split the state's congressional evenly, each triumphing in seven.

Counting Tuesday's other primary, in Arizona, Michigan's split primary still leaves Romney with a substantial delegate lead overall. He won 44 delegates from both states on Tuesday, bringing his overall count to 153. Santorum took home 15 delegates from Michigan on Tuesday and zero from the winner-takes-all state of Arizona, bringing his total to 87.