A growth zone straddling the Woodbury-Cottage Grove border is poised to become perhaps the fastest-growing part of the metro area.

If projections pan out, an area that is mostly farmland and fields will be home to 24,000 people in as little as 10 years.

Developers have started work on five projects, and two more are planned. And other developers are sniffing around, waiting for the right opportunity.

“Activity drives activity,” said Cottage Grove city administrator Ryan Schroeder. “There is an awful lot of interest in northern Cottage Grove right now.”

The growth zone includes the fastest-growing parts of two growing suburbs.

From 1990 to 2012, Cottage Grove grew 52 percent, to a population of 35,000, according to the U.S. census. Woodbury more than tripled, to 65,000.

The new growth would include 20,000 people expected in Woodbury’s Phase 2 area and 4,000 more projected for northern Cottage Grove.

One reason for the growth? How neighbors feel about Woodbury.

To the east in Afton, for example, many see Woodbury’s growth as a threat. The city is considering a new kind of zoning along the Woodbury border, meant to stem the spread of development.

To the south of Woodbury, Cottage Grove is taking the opposite approach. “We see Woodbury as a partner,” Schroeder said.

Cottage Grove has planned for years for growth near its border with Woodbury. Now the two cities are cooperating, building roads that will connect their residential projects.

Schroeder said the residents of the two-city zone will have much in common. “They will drive the same streets and shop the same malls,” he said — and much of the time, they send their children to the same schools.

Feeding the anticipated growth are available sewer and water connections, according to Dwight Picha, Woodbury community-development director. A large sewer line runs through the area, along County Road 19, which is Keats Avenue in Cottage Grove and Woodbury Drive to the north.

Of course, many cities plan for growth that doesn’t happen as expected. Ultimately, it is developers, not city leaders, who build neighborhoods. But in the Woodbury-Cottage Grove growth zone, developers are busy.

Phase 2 developments already underway in Woodbury include:

— Southridge, on Dale Road, which eventually will include more than 200 homes.

— Ashton Ridge on Mile Drive with 127 homes.

— Bailey Lake, next to Ashton Ridge, with 97 homes.

Next year, construction is expected at two others: Bielenberg Gardens, a retail and residential “urban village,” at Radio Drive and Bailey Road; and a Maplewood Development residential project on Dale Road.

In Cottage Grove, projects include:

— The 134-lot Eastridge Woods on 70th Street, which is underway.

— A 92-lot project by Newland Homes, next to Eastridge Woods, expected to begin next spring.

The Cottage Grove growth is in the East Ravine Development Area — a 4,000-acre L-shaped parcel north of 70th Street and mostly to the east of Keats Avenue.

Developers showed relatively little interest in East Ravine until the kickoff of Woodbury’s Phase 2 project.

Phase 2 is a swath of more than 2,000 acres south of Bailey Road. It is planned to eventually have 6,000 homes, half of them single-family houses and half apartments and townhomes.

Schroeder said that when plans for Woodbury’s Phase 2 began to unfold, Cottage Grove didn’t have lots nearby to sell. Cottage Grove is now catching up — and more developers are showing interest, he said.

It’s impossible to guarantee any projections, but the Phase 2 growth is on track so far, according to Picha. He said about 600 homes are scheduled to be built next year.

Two experts in local development said the area will be one of the fastest-growing — if not the fastest — areas in the metro area in the next 10 to 15 years.

Mary Bujold, president of Maxfield Research, a real estate research firm based in Minneapolis, said there might be similar growth potential in “similar communities with similar access” — including Chaska and Chanhassen. But they probably would not surpass the 24,000 population increase anticipated for the Woodbury-Cottage Grove zone.

Likewise, Rick McKelvey, assistant vice president in development at United Properties, couldn’t think of another area of the metro area projected to grow as quickly. United is managing the retail part of the Bielenberg Gardens development.

Bob Shaw can be reached at 651-228-5433. Follow him at twitter.com/BshawPP.