BELFAST, Maine — The Maine Judicial Branch has chosen a site near the Superior Court building for Belfast’s new downtown courthouse.

The state has signed a pair of purchase-and-sale agreements for property bordered by Church, Market and Anderson streets, Mary Ann Lynch, government and media counsel for the state agency, said Wednesday in an email. It plans to build a roughly 30,000-square-foot courthouse in the area, which is currently home to Duval’s Garage and a single-family home.

“Waldo County hosts two of the oldest, most inefficient, and inaccessible courthouses in the state,” Lynch said.

Early this year, the state released its early plans for a $17 million courthouse project to replace the existing Superior Court and District Court buildings in Belfast. The Waldo County Courthouse, which houses the Superior Court, is 162 years old and doesn’t conform to handicapped accessibility requirements. It’s showing its age, with electrical and mechanical system failures, and wasn’t designed in a way that eases modern security concerns, according to the state.

The district court building was designed in 1930 and added onto in 1987, but it has accessibility problems of its own and “does not provide separate and safe circulation paths for judicial staff, incarcerated defendants, jurors and the public.”

The judicial branch has been pushing to consolidate courts and replace aging courthouse buildings in counties across the state in an effort to run them more efficiently and cut costs long term. In recent years, the state has modernized courts in Bangor, Augusta, Houlton, Dover-Foxcroft and Machias.

North Peak Architecture, based in Presque Isle, has been hired to design the new Belfast courthouse, a process expected to take about half a year. Construction is expected to start next summer and wrap up about June 2018.

Waldo County owns both existing court buildings and plans to continue using them.

“We have extremely crowded offices in Waldo County, and we have for years,” William Shorey, county commission chairman, said Friday.

The Superior Court building, a downtown landmark, will remain in use as office space on the first floor. The second story, where the courtroom is located, may be temporarily sealed off to reduce heating costs, Shorey said. The county may lease some space in other parts of the building.

The District Court building will remain fully occupied after the court’s departure, once offices are shuffled around and county employees allowed to spread out, Shorey added. Both former court buildings would require renovations, which Shorey estimated could cost $500,000 to $700,000.

“We’re excited, we’ve needed [a new courthouse] for years and years,” Shorey said.

Belfast Mayor Walter Ash, after hearing about the purchase-and-sale agreements Wednesday, said he was pleased to hear the state had selected a downtown site. There was some concern among city leaders that the state might select a plot of land on the outskirts of town.

“We’re pleased they’ve decided to stay in the heart of things here in the downtown,” Ash said.

Follow Nick McCrea on Twitter at @nmccrea213.