President Obama and the foundation helping to plot his path after the White House have selected Jackson Park on the South Side of Chicago as the site of his presidential library, ending a debate within his inner circle about the location, a person familiar with the decision said Wednesday.

Mr. Obama and his presidential foundation have been deliberating for months over whether to place the library in Jackson Park, which is on a broad expanse of Lake Michigan and borders the Woodlawn neighborhood, or in the Washington Park neighborhood, which is closer to the Obamas’ home in Chicago.

Even when the Barack Obama Foundation announced it had selected architects for the project this month — choosing the New York husband-and-wife team of Tod Williams and Billie Tsien — it had still not made its final choice of sites.