INDIANAPOLIS — Barack Obama’s historic presidential win that also turned Indiana from red state to blue drew heavily on first-time voters, blacks and the college-age voters his campaign aggressively courted, political observers say.

To win Indiana, the Illinois senator targeted voters in the traditional Democratic strongholds of Lake, Marion and Monroe counties even as he siphoned away the votes of Republicans, moderates and independents from John McCain.

Obama secured Indiana with a strategy that included nearly 50 visits this year to the state and heavy spending on campaign commercials in the state’s television markets, said Robert Schmuhl, a political analyst and University of Notre Dame professor.

“His visits to Indiana received so much media attention that Hoosiers saw how seriously he took this state,” Schmuhl said Wednesday. “It’s remarkable that on Election Day that he made the effort to return to Indiana for his very last campaign stop.”

Obama, who defeated McCain by about 26,000 votes out of some 2.7 million cast, according to unofficial results tallied by The Associated Press, picked up 10 Indiana counties that President Bush had won in 2004.

Among those 10 counties, Obama’s biggest “flip” was St. Joseph County, home of South Bend and Notre Dame. Unofficial vote totals show Obama defeated McCain by 20,198 votes in the county, which Bush carried in 2004 by just 2,617 votes.

Obama, who became the first Democratic presidential candidate since Lyndon Johnson in 1964 to win Indiana, focused heavily on registering new or young voters and getting out their vote, while also targeting older independent-minded voters.

An AP exit poll showed that about a quarter of Indiana voters described themselves Tuesday as independents and that more than half of that group favored Obama over McCain.

The AP exit poll results from 2,422 Indiana voters also showed that Obama collected the votes of more than six out of 10 of Indiana voters between the ages of 18 and 29.

For these young voters, many of them upset with nation’s economic turmoil as they prepare to enter the job market, Obama’s message of change resonated strongly, said William Kubik, a professor of political science at Hanover College in southern Indiana.

Kubik said the experience of helping elect the nation’s first black president amid his calls for progressive change could have a lasting effect on these young voters’ future voting habits.

“Young people are notoriously unanchored in their voting behavior, and their first political experiences often have a molding experience on how they view politics in the future,” he said.

“In the 1980s, young voters came of political age during the Reagan years and they tended to become or to identify with Republicans. I really wonder if we’ll see something like that with Obama.”

Kubik said Obama reached out to northern Indiana voters by buying expensive Chicago television time to send his message to some of northern Indiana’s big population areas, and he did the same in the Louisville, Ky., market to reached southern Indiana voters.

“He really blitzed the state with advertising. I was amazed at how many Obama ads we saw this cycle relative to McCain ads. He did a really good of focusing on health care, financial concerns — the issues that appeal exactly to moderate voters,” he said.

Obama also got some help from Republicans in his Hoosier victory. He collected the votes of nearly 10 percentage points more self-described Republicans than Democrat John Kerry did in 2004, according to the AP exit poll.

A day after Obama’s win, McCain supporters at a Crown Point restaurant called A Conservative Cafe expressed grudging admiration for his campaign.

Lorne Aubin, a 47-year-old banker from Bloomington, conceded that Obama ran a “great campaign” against the Arizona senator.

“No question he outcampaigned McCain. With this economy, no one could have won against him,” she said.