"We were 100 percent maxed out down there," Sheffield said. "This new office will give us breathing room down there."
Sheffield said the new post office at 12912 Conomar Drive was built in response to the area's recent growth and will make the city's delivery system more efficient.
It also will ease parking woes at the downtown office, Sheffield said.
The 18,000-square-foot facility cost about $5.5 million to build and is twice the size of the Northern Avenue office, which was 8,000 square feet.
Northern Station is open Monday through Friday from 8:30 a.m. to 5 p.m., and Saturday from 8:30 a.m. to noon. The lobby is open 24 hours.
Customers may purchase stamps, boxes and gifts, and can send and receive mail at Northern Station.
Before the new post office opened, residents living in the 21742 ZIP code could only send and receive mail at the Northern Avenue location, said Floyd Atherton, interim station manager at the new post office.
Atherton said residents had to pick up larger packages from the downtown office, and the lobby at Northern Avenue closed at 5 p.m.
The office did not deliver mail to households in that region, Atherton said.