A Google Fiber program launched nearly five years ago will expand to 18 cities in the Atlanta, Charlotte, Nashville and Raleigh-Durham areas.
"We can't wait to see what people and businesses across the southeast US do with gigabit speeds," Google Fiber vice president Dennis Kish said in a blog post announcing the expansion Tuesday.
Google Fiber is live in Kansas City, Provo and Austin.
Google is meanwhile working on a new generation of applications designed to capitalize on Internet speeds available using Fiber, but did not disclose details.
"Today, we aren't the only ones talking about gigabit broadband," Kish said.
"From the White House to main street, a chorus of new voices is standing up for speed."
Some US telecommunications firms stepped up with higher-speed Internet plans of their own after Google started weaving Fiber into cities.
Expansion of the Fiber program comes amid media reports that Google is getting ready to sell wireless telephone services directly to US consumers after reaching deals with carriers T-Mobile and Sprint.
The move would have a big impact on the US wireless industry, potentially resulting in price cuts and improved speeds.
Google is already in a powerful position in the wireless world, with its Android operating system running on more than 80 percent of the world's mobile phones.