The partnership behind Konterra, one of the largest planned development projects in Prince George’s County, is no longer.

The Gould family and its real estate company, Gould Property Co., own 2,200 acres along Interstate 95 in Laurel that it has been plotting for years as a colossal mixed-use development with partner Forest City Washington, the local arm of Cleveland-based Forest City Enterprises.

The plans are ambitious. With land totaling nearly two-thirds the size of Tysons Corner, Gould and Forest City planned a 488-acre, multibillion-dollar town center project near the intersection of I-95 and the Intercounty Connector that promised 4,500 residential units, 5.3 million square feet of commercial, retail and office space, and 500,000 square feet of hospitality space.

Konterra Town Center East’s downtown would feature a town square and promenade lined with upscale shops that some hoped would also deliver a high-end department store.

The partners, however, have parted ways. Deborah Ratner Salzberg, president of Forest City Washington, disclosed in an interview last week that the two companies were now operating on a “on a nonexclusive basis.”

Ratner Salzberg referred further questions about the partnership’s dissolution to the Gould Co.

Kingdon Gould III, of Gould Property, said Konterra was proceeding. “We want to begin building organically into the town center, and we are beginning to do that with some housing and associated retail,” he said.

Gould also said there were no sour feelings about the break-up.

“We have nothing but good things to say about the folks at Forest City,” he said.

The Goulds could select another development partner to help complete the project, but the end of the Gould-Forest City partnership comes after the two companies put years of work into planning the project and building support with elected officials.

Konterra and Forest City, which specializes in major mixed-use public-private developments, received many of the needed approvals from the county in 2009, when the Prince George’s County Council and the county planning board approved Konterra’s site plan. In 2011, the Goulds entered a joint agreement with state and county officials to make way for an extension of the Intercounty Connector to the project.

Forest City officials marketed the project to retailers at the International Council of Shopping Centers’ conference in Las Vegas. After returning from the 2010 conference, Tom Archer, vice president for development at Forest City Washington, said he expected Konterra to feature a “fashion-oriented mix” and that there was a “high degree of department store interest.”