Area residents got their first in-depth look Thursday at 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 overdeveloped 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 housing the newspaper’s operations and parking lots.

As envisioned, between Meeting and St. Philip streets there potentially could be upwards of 2 million square feet of new buildings and parking structures, plus shopping sites and eateries. Other opportunities include green space, parks and mass transit links.

On Thursday, the city’s Department of Planning, Preservation and Sustainability hosted a forum on the project, drawing about 25 people interested in how the development plays out. It was one of a slew of meetings and approvals needed before the project becomes a reality. This one was more informal, though.

Some locals gave their input. Chris Maloney of the Cannonborough-Elliotborough Beautification Committee spoke in favor of the project’s first phase, to develop the corner of Meeting and Columbus streets, across from the neighboring business Piggly Wiggly supermarket.

There’s “no reason Meeting Street can’t have the same retail flair” that King Street has, Maloney said.

Another C-E neighborhood representative said the site had the potential to become a “great” destination site for living, working and shopping.

But “to pass the test of time, you have to add green space,” neighborhood association president Tim Muller said after the meeting.

The company’s plans are expected to extend the redevelopment of upper King and Meeting streets as far as Line Street near Interstate 26, part of a gradual increase in activity north seen in recent years. Other parts of the master plan anticipate as many as 450 residences, more than 900,000 square feet of retail and office space and three parking garages with more than 2,100 spaces.

City Planning Director Tim Keane sounded optimistic, saying the effort had the potential to be “a new Charleston Place,” referring to the popular hotel and shopping layout between lower King and Meeting streets.

Another community meeting is scheduled for the night of Dec. 5, with the East Side Neighborhood Association at its gathering building on America Street.