The developers of City Springs, the new town center and municipal complex for Sandy Springs, said Thursday they have closed on the purchase of land to begin construction of the private side of the project.

Atlanta real estate firms Carter and Selig Enterprises are the master developers of the complex to create a downtown for the north Fulton County city from what was formerly a stretch of strip malls at Johnson Ferry and Roswell roads. The public-private partnership will include a new city hall and performing arts center, meeting space, green space, retail and nearly 300 residences.

Development of critical infrastructure and the city-controlled part of the project has been underway for about a year, but the closing of the private side of the deal marks the start of residential and retail pieces of the project, Carter Executive Vice President Jerome Hagley said.

“It doesn’t look like a big site, but it’s a big site with a lot of activity going on,” he said.

The budget for the public part of the project was set at about $180 million earlier this year. Carter and Selig have not disclosed the value of the private development. The land price for the two parcels was $7.35 million, according to Sandy Springs spokeswoman Sharon Kraun.

Hagley said the Selig team last month went to Las Vegas to pitch the project to retailers and restaurant groups at the noted International Council of Shopping Centers annual convention.

“We’ve got a lot interest on the retail space,” Hagley said.