Ron Kaplan of Streetscape Partners and Robert Goodill of Torti, Gallas & Partners on the site in Clarksburg. (Jeffrey MacMillan/JEFFREY MACMILLAN)

A pair of developers have unveiled plans for nearly 450,000 square feet of outlet shopping off of Route 270 in Clarksburg, a project on par with the Leesburg outlet plaza that could derail a competing outlet plan for Ten Mile Creek.

Bethesda-based Streetscape Partners and New England Development, a Massachusetts firm, have signed a contract with Adventist HealthCare to buy 47 acres on the west side of I-270 just south of Clarksburg Road. They plan to build an outlet center that Ron Kaplan, co-managing principal of Streetscape Partners, said would resemble a “next generation” version of the Leesburg outlets to be called Clarksburg Premium Outlets at Cabin Branch.

The developers are planning the project in partnership with Simon Property Group, the country’s largest operator of malls and one of the largest real estate companies in the world. Simon’s Leesburg outlets include more than 120 stores, including Burberry, Coach, J. Crew, Nike and Vera Bradley.

“Montgomery County doesn’t have that kind of retail anywhere,” Kaplan said.

Before co-founding Streetscape Partners in 2008, Kaplan had served as chief investment officer at Federal Realty Investment Trust, a Rockville retail developer that built Bethesda Row and is now building the Pike & Rose project in White Flint.

Kaplan said the Adventist property was “literally one of the best pieces of retail land I have ever seen” because of its visibility and access from I-270 and years Adventist spent planning for a hospital there for which it ultimately never won approval. Road improvements as well as water and sewer connections are already being made even though the sale of the land has not closed.

“We stepped on top of a piece of land where the lion’s share of work had already been done,” Kaplan said.

Michele Rothstein, a senior vice president for marketing at Simon, issued a statement saying that the next phase “will assure that we continue to build a community-oriented neighborhood in Cabin Branch that will attract many of the finest designers and leading brands to Clarksburg, while creating more than 1,500 full-time employment opportunities.”

Although the project still requires some approvals, Kaplan said construction could begin in late 2014 and the outlets could open in 2015. That timeline hinges, however, on the project not requiring a master plan amendment, which is not likely to be decided until a July 18 planning board meeting. “They have to show that it’s consistent with the existing master plan,” said John Carter, planning chief for northern Montgomery County, said of the developers.

The Peterson Cos., which has spent thousands of dollars planning a Tanger outlet project for Ten Mile Creek, is betting that the Simon plan will require a similarly lengthy approval process. It’s unlikely that Montgomery County can support both projects, but Kaplan said it’s not a contest over which project will prevail.

“There’s not a retail war because theirs is the roughest of concepts,” he said. “In a room we’re all good at drawing up plans, but then they’ve got this multi-year process.”