CHAMBERSBURG, Pa. — Franklin County, Pa., government unveiled plans Wednesday for a $67.8 million overhaul of its court and administrative offices.

The plan calls for a new structure in the first block of North Main Street to be paired with the historic courthouse for most judicial functions.

The structure currently known as “the annex” facing Lincoln Way East would house support functions such as juvenile probation.

The initial proposal also would involve renovating the “administrative annex” structure on North Second Street for public meeting spaces, the commissioners’ offices, voter registration, the treasurer and similar offices. An archives building would be constructed on that site.

“The safety, security and inefficiency of our courthouse and related offices is a very real problem,” said David Keller, chairman of the Franklin County Commissioners. “The information that was presented to us (Wednesday) is certainly a comprehensive and well-thought-out solution to the problem, and is definitely worthy of our consideration.”

John Hart, a former county administrator, is serving as project manager for the judicial center.

Hart said the last major courthouse renovation was done in 1979, when the county had two judges and four people in its district attorney’s office.

The county now has five Court of Common Pleas judges and 26 employees in the district attorney’s office.

“Since 1979, we’ve had a 30 percent increase in population,” Hart said.

The county added 4,000 square feet to its judicial facilities in 2010 and 2011 based on a needs study done in 2009.

Court of Common Pleas President Judge Carol Van Horn said the study determined that the county needed 40,000 square feet, but got 4,000 square feet in the most recent renovation.

She echoed a plea for better security, based, in part, on Franklin County Jail Warden Bill Bechtold’s estimate that 30 people currently are incarcerated for homicide.

The new proposal from Noelker and Hull Associates and Silling Architects would create an additional 166,000 square feet. It would create what are called “circulation systems” to keep the public, staff members and defendants isolated from each other.

A bond consultant said the county’s existing debt should be paid off in 2024.

“This allows this new borrowing to come in at a low millage impact,” John Frey said, referencing the way Pennsylvania’s property taxes are based on mills.

Frey estimated a new 1.5 mills of taxes would be needed since each mill generates $1.5 million annually for the county.

For a taxpayer, one mill represents $1 for every $1,000 assessed property value.