The long retreat of the DuPont Co. from the city it long personified took a giant leap Monday when the chemical-maker announced it would move about 1,000 employees, including its chief executive officer, from the center of troubled Wilmington to a suburban office park.

DuPont said Monday it will consolidate its headquarters. Between 800 and 1,000 supervisors and staff will leave the high-rise complex that has loomed over the city's focal Rodney Square Park since Pierre S. du Pont created the modern company in the early 1900s.

The destination will be the Chestnut Run Plaza office park in New Castle County, west of the city. The move is effective July 1.

"DuPont Co. has been leaving the city and state for a decade or more," said New Castle County Executive Tom Gordon. Gordon blames free-trade agreements that have made it cheaper to manufacture abroad, and aggressive DuPont shareholders such as billionaire Nelson Peltz, who has publicly urged DuPont chairwoman Ellen J. Kullman to cut management expenses, sell business lines, and do more to enrich investors.

A spokeswoman for Peltz and his Trian Partners fund, based on Park Avenue in New York, declined to comment.

"We need to get jobs back," added Gordon, who is also the county's former police chief. "The corporations that are running this country are not building here. I don't know how much more people can take before there's a revolution."

Another 800 to 1,000 workers will remain at the headquarters complex, for the time being, as employees of DuPont's Performance Chemicals business, said company spokesman Daniel A. Turner.

DuPont is spinning off that group of businesses into an independent corporation, Chemours (pronounced KEM-oars) Co., which has not yet chosen a permanent headquarters. Those businesses, which include DuPont's Edgemoor plant on the Delaware River north of Wilmington, account for about $7 billion of DuPont's $35 billion in yearly sales.

Wilmington and state officials are trying to persuade Chemours to stay, according to a statement from Mayor Dennis P. Williams.

Delaware officials were unable to persuade DuPont's 2013 spin-off, Axalta Coating Systems, to keep its headquarters there. Axalta moved its offices to Philadelphia and Glen Mills, Delaware County.

Its profits swollen by war-supply sales, synthetic materials like nylon, and timely investments in General Motors, a major customer, DuPont was the most-valuable publicly traded U.S. company for a time in the 1950s. It remains the only Philadelphia-area company listed on the Dow Jones index of 30 large industrial stocks.

In 1970, activist Ralph Nader published a fat book called The Company State that detailed how DuPont dominated local politics, economics, and society in Delaware. Back then, a quarter of the legislature and about 10 percent of the state workforce were employed by DuPont. The company's factories, charities, and founding family estates dominated the landscape.

By the late 1990s, DuPont had reduced its local workforce to less than 10,000, through spin-offs, asset sales, early-retirements, and the shuttering of its former engineering center at Louviers, west of Wilmington. The banks that replaced it as the state's major employers have since been sold to out-of-state companies, further reducing local office employment.

DuPont sold the Wilmington headquarters complex to local developers Buccini/Pollin Group in 2000, and has steadily cut back its occupancy there in the years since, notes Pete Davisson of Jackson Cross Partners L.L.C., a Wilmington commercial broker.

"The sale of the buildings was the beginning of the DuPont exit strategy," Davisson said.

DuPont is leaving the downtown as Wilmington, the state's largest town with a population of 71,000, struggles with one of the highest urban violent-crime rates in America, according to FBI statistics that have won the city unwelcome attention from national media, including a recent Newsweek story titled "Murder Town USA."

Williams, the mayor and a former city police officer, has encouraged the formation of the force's first permanent homicide unit in response to dozens of unsolved shootings in the city's poorer neighborhoods.

Asked if Wilmington taxes, city services, or operating costs were factors in leaving town, Turner, the city spokesman, said the consolidation was driven more by the company's reorganization and the Chemours separation.

"The consolidation of DuPont corporate headquarters at Chestnut Run will optimize use of company facilities, support collaboration, and improve efficiencies for both DuPont and Chemours," the company said in a statement.

DuPont will continue to operate the Hotel du Pont and the DuPont Theatre at Rodney Square, as well as the DuPont Country Club in the nearby suburbs, Turner said.

"For more than a century, we have been proud to call the city of Wilmington home," said Kullman, a suburban Wilmington native. But, she added, "looking ahead, we concluded that a single location for our headquarters offices will help facilitate the close collaboration essential to our success and to the growth of DuPont."

The company also noted the new headquarters is close to the Brandywine Creek site where the company's immigrant founder, Eleuthere Irenee du Pont de Nemours, set up his gunpowder factory in 1802, and just down Delaware Route 141 from the DuPont Experimental Station, the laboratories occupied by DuPont scientists, engineers and business partners.