J. Lynn Cornwell Jr. ran his family’s slaughterhouse in Purcellville, Va., until it closed in 1977. (Eugene Scheel/For The Washington Post)

J. Lynn Cornwell Jr., a Loudoun County real estate investor and developer and the last in his family to manage the Cornwell-owned slaughterhouse in Purcellville, Va., died July 9 at his home in Middleburg, Va. He was 89.

The cause was Parkinson’s disease, said a daughter, Linda Wright.

In business and real estate, Mr. Cornwell was known as the developer of Valley Industrial Park in Purcellville and of various apartment complexes in Loudoun County. From 1984 until 2008, he was a director of the Middleburg Bank.

For generations, his family name was associated with the slaughterhouse. Until the business closed in 1977, Mr. Cornwell and his brother, Brewster, ran the Cornwell & Son abattoir, which since the 1920s had served hog and cattle farmers not only in the Mid-Atlantic region but as far away as New England and Nebraska.

In its peak years of operation, Cornwell’s, as it was known locally, slaughtered as many as 10,000 cattle a year. This was in the early 1930s, according to a Washington Post story written by historian Eugene Scheel in 2008. They were “brought in by rail, penned by the tracks, driven down the Hillsboro Road to the plant, then slaughtered and refrigerated,” Mr. Cornwell told Scheel.

Later the Cornwell operation began concentrating on hogs — its record was 2,100 hogs a day during the World War II years — and its workforce peaked at 100, making Cornwell’s one of the largest employers in the Piedmont region, and a major supplier of hams and bacon.

The inedible portions of the hogs were also valued products, converted after cooking to chicken feed, and grease, which was made into soap. Various glands, such as the thyroid, pituitary and pancreas, were sold to drug companies.

Like slaughterhouses everywhere, Cornwell’s produced a distinct, powerful and unpleasant odor. When the plant opened, the smell wafted across nearby fields and woods, most of which were uninhabited. Not so in the 1960s. The fringes of metropolitan Washington were expanding into Loudoun County, and the fields and woods around Cornwell’s were filling up with houses. Residents found the slaughterhouse smell offensive.

“I’d be at a Little League game, and someone would come up to me, ‘What are you going to do about that smell?’ ” Mr. Cornwell said.

Jacob Lynn Cornwell was born Nov. 2, 1924, in Purcellville. He graduated from Virginia Military Institute in 1944. During World War II, he served in an Army artillery unit in Europe.

He began working at the family slaughterhouse after the war. During the Korean War, the Cornwell operation expanded to the point where hogs from midwestern farms were purchased by telephone, then picked up by Cornwell trucks and driven to the Purcellville slaughterhouse within 12 hours.

By the early 1970s, business had declined. Several top customers went bankrupt. Farming and agriculture in the Piedmont area were no longer the prestige and status operations they once had been. The slaughterhouse closed during the summers of 1975 and 1976, and it shut down for good in April 1977.

Few were sorry to see it go.

“There never was one card or expression of sympathy,” Mr. Cornwell said. His brother Brewster Cornwell, who died last year, told Scheel, “I bet they shouted hallelujah.”

The building was sold and remodeled into a white-collar commercial and office center. “That’s the way life goes,” Mr. Cornwell said. “If you don’t change with it, you’re in real trouble.”

Mr. Cornwell was a member of the board of Leesburg Hospital and the Loudoun County Sanitation Authority. He was a golfer and tennis player.

His wife, Jean Humphrey Cornwell, whom he married in 1950, died in 2007. Survivors include two daughters, Linda Wright of Middleburg and Susan Cornwell of Parker, Colo.; two granddaughters; and a great-granddaughter.