Thomas Voss, a top trainer of steeplechase and flat race horses, died suddenly at his Monkton farm on Tuesday.
His family confirmed the death of Mr. Voss, who was 63. The cause was an apparent heart attack.
"This is a great loss. We are all just stunned," said Maryanna Skowronski, a longtime friend of the Voss family, who is director of the Historical Society of Harford County.
Though Mr. Voss trained both flat and steeplechase runners, his greatest success was with the latter. He was a five-time National Steeplechase Association top trainer, most recently in 2011. Among the top horses he trained was 2010 Eclipse Award steeplechase champion Slip Away.
He also holds the distinction of training the oldest horse to win a Grade I race on the flat, John's Call, winner of the Sword Dancer International at age 9 at Saratoga Race Track in 2000. John's Call also won the Grade I Turf Classic Invitational Stakes at Belmont Park the same year.
Mr. Voss started out as an amateur timber rider and began training professionally in 1973. According to his biography on the National Steeplechase Association website, his first winner was with Aruhapy at the My Lady's Manor races in Harford County in 1973.
Atlanta Hall, the Voss family's farm in northwestern Harford County, is home to the annual Elkridge-Harford Point-to-Point Races, which kicks off Maryland's timber racing season each spring.
The Voss family has long been active in land preservation, and the farm has been a steeplechase and fox hunting venue since the 1930s.
Mr. Voss is survived by his wife, Mimi, a son, a daughter, a stepson and four grandchildren.
Services will be held at 10 a.m. Monday at St. James Episcopal Church, 3100 Monkton Road.
Jacques Kelly of The Baltimore Sun contributed to this report.