Linden Hill, the Gladwyne estate once owned by Campbell Soup heir John T. Dorrance Jr., is on the market for $24.5 million.

The secluded, 50-plus-acre property at 1543 Monk Rd., with its 14,000-square-foot, 20-room Norman-style manor house, formal gardens, orchards, two swimming pools, pool house, and tennis court, has been owned since 1999 by Robert L. and Susan Burch.

Burch and his brother, J. Christopher Burch, were co-founders  Eagle Eye, a retailer of outdoors sportswear they have since sold.

Robert Burch is chief executive officer of UgMO Technologies of King of Prussia, which develops irrigation systems. He declined to be interviewed.

The property listing was activated Monday in time for the start of this week's U.S. Open at Merion Golf Club. John C. Dubbs and Eleanor Morsbach Godin, of Prudential Fox & Roach in Malvern, believe the tournament will give the residence national exposure.

"All eyes will be on Philadelphia," Dubbs said.

The very high-end properties tend to be marketed to out-of-town buyers, primarily New Yorkers, Europeans, and Asians, as well as the area's well-to-do.

Research in 2009 by Center City developer Tom Scannapieco found perhaps 2,000 people in the Philadelphia metropolitan area with a net worth in excess of $10 million.

Dorrance, son of the inventor of condensed soup, was considered one of the richest men in the world. His 31 percent portion of Campbell's stock was worth $1.6 billion, and his annual income exceeded $40 million.

He was Campbell's chairman for 22 years, and bought Linden Hill in the 1950s.

The property was designed in 1929 by the architect Edmund Beaman Gilchrist, known for his Norman designs, and built over two years by J.S. Cornell & Sons for Rodman E. Griscom, son of Philadelphia shipping magnate Clement A. Griscom.

This is only the second time Linden Hill has been for sale since Dorrance's death at 70 in April 1989.

In June 1992, John H. Foster, now chairman and managing director of HealthpointCapital in New York, bought the property from the Dorrance estate for $5.75 million.

Foster, who founded NovaCare, a Valley Forge rehabilitation facility that he has since sold, bought 80 of Linden Hill's 109 acres from the estate's executors and lived there with his wife, Lynn.

They sold the property to Burch in August 1999 for $9.3 million, Montgomery County records show.

The manor house is the centerpiece of the estate. It has a central entrance hall; a living room and dining room flanked by two wings that house the modern kitchen; family living spaces; seven bedrooms for family, with eight full baths and three half-baths; and staff quarters with two to three bedrooms.

The ceilings are from 10 to 14 feet high. The paneling was intricately carved by hand, there are eight fireplaces, and the flooring is English oak.

Every room has a view, and most have French doors that open to the surrounding gardens.

Outbuildings include a two-story guesthouse with living room, dining room, kitchen, two bedrooms, two baths, and a garage; a turreted caretakers' house with four bedrooms and two baths; a staff/guest cottage; a 10-car garage; a barn with horse stalls; an aviary; and a wood shop.

Linden Hill is not the region's priciest listing. That honor goes to 464-acre Fashion Farms in New Hope, which went on the market in October for $50 million. Jules Siegel, its owner, will sell the property only as a single entity for breeding horses.

On the market at $25 million is 770 Godfrey Rd. in Villanova. Known as Albermarle, it has 17 acres and a large house that was once part of the 745-acre tract owned by Col. Robert Montgomery.

According to the June/July issue of Unique Homes magazine, the most expensive property for sale in the United States is Copper Beech Farm in Greenwich, Conn., listed May 14 at $190 million.