For Obama, the raw math suggests a slight advantage. Upward of 25 percent of the primary vote will come out of just two counties: Marion County is home to Indianapolis, the capital and state's largest city, and Lake County is home to industrial Gary, located in the northwest corner of the state and part of the Chicago media market.
Both will strongly favor the Illinois senator, Indiana political observers predict, thanks in part to large African-American populations.
According to Robin Winston, a former Indiana Democratic chairman who hasn't endorsed in the race, 253 precincts in the state have delivered more than 90 percent of the vote to Democrats in recent elections -- and 241 of them are in the Indianapolis-based 7th District and the Gary-based 1st.
Both places have quirks that are likely to benefit Obama.
In Lake County, Obama was a household name well before the presidential race.
"The northwest part of our state considers itself part of Chicago," says Matthew Tully, political columnist for the Indianapolis Star and a Gary native. "They get Chicago TV and read Chicago papers and have been watching Obama grow up as a politician for years now."
In Marion County, Obama's already well-oiled grass-roots operation will get a boost. Rep. Andre Carson, who just succeeded his late grandmother in a special election, will face off against three credible Democratic challengers, spiking turnout numbers in the hotly contested Democratic primary.
"If he wins huge in the cities, it makes it harder to overcome in other places," notes Tully.
In other words, Clinton could win the vast majority of counties in the state and still lose. "We have 92 counties, and if he wins the right five, he's OK," said one Indiana Democratic insider.
That's because, contrary to some stereotypes, Indiana's population is largely packed into small and medium cities -- not spread out in rural areas. It's more than 70 percent urban, and 30 of the state's counties produce 81 percent of the vote.