The changes in Indiana, announced Thursday, are expected to eliminate at least 354 jobs and save at least $39.8 million.

Mail operations in Bloomington, Columbus, Kokomo, Lafayette and Muncie will be moved to Indianapolis, according to a United States Postal Service news release.

Terre Haute mail operations will be split between Indianapolis and Evansville, while South Bend operations will be moved to Fort Wayne. Gary processing will be moved to Bedford Park, Ill.

There will be no change to the retail operations at the locations, USPS officials said.

"The decision to consolidate mail processing facilities recognizes the urgent need to reduce the size of the national mail processing network to eliminate costly underutilized infrastructure," said USPS Chief Operating Officer Megan Brennan. "Consolidating operations is necessary if the postal service is to remain viable to provide mail service to the nation."

The closures are the result of a five-month efficiency study after the USPS experienced a 25 percent drop in first-class mail volume since 2006.

The Postal Service is proposing to close 223 mail processing centers nationwide as a larger comprehensive plan to cut operating costs by $20 billion by 2015.

Spokeswoman Mary Dando says the closings will take effect unless Congress approves five-day mail delivery and proposed changes in retirement funding for postal workers. The Postal Service did not announce when the changes would take place.

Specific dates have not been set for the closures.