Area residents got their first in-depth look tonight at the Evening Post Publishing Co.’s plans to develop 12 acres around King and Columbus streets into a mix of residential, retail and commercial businesses in a project expected to define the upper King corridor for decades to come.

A representative of a leading preservationist group called it the most significant building project the city will see in the next 15 years.

“It’s a great opportunity,” said Robert Gurley, director of advocacy for the Preservation Society of Charleston.

Gurley cautioned, though, that the project, dubbed “Courier Square,” does not become so big that it overwhelms surrounding neighborhoods by being over-developed or too densely situated.

Earlier this year, The Post and Courier’s parent company announced plans to build up the spaces around the newspaper’s main building in stages and over the next 10-to-15 years.

Nearly three city blocks are in play, including the building that houses the newspaper’s operations and parking lots.