Rose Paterson, the chairman of Aintree Racecourse, has been found dead at her Shropshire home aged 63.
She was married to Conservative MP and former cabinet minister Owen Paterson.
In a statement, he said the loss of his wife had come as a “terrible shock” to the family. A cause of death has not been given.
“It is with great sadness that I must inform you that my wife, Rose, has been found dead at our family home in Shropshire,” he said.
“Rose and I were married for 40 happy years. She was a wonderful, caring wife, mother and grandmother.
“Her death has come as a terrible shock to us all. I would ask the media to respect the privacy of myself and my family at this extremely difficult time.”
The couple married in 1980 and had two sons and a daughter.
A minute’s silence was held before racing at Haydock on Wednesday in her memory and that of Grand National-winning jockey Liam Treadwell, whose death was announced on Tuesday.
In a statement West Mercia Police said: “We can confirm the body of a woman has been found in woodland near Pant Lane in Sodylt in Ellesmere. The death is currently being treated as unexplained. However at this stage, there is believed to be no third-party involvement.”
Prime Minister Boris Johnson has offered his condolences to Mr Paterson and his family.
“The PM heard the news this morning and has written to Owen,” said a Downing Street spokesman.
“His thoughts and every sympathy are with Owen, his children and grandchildren at this difficult time.”
‘She will be missed greatly’
Paterson, the daughter of the fourth Viscount Ridley, was on the main board of stewards at the Jockey Club, which owns Aintree Racecourse, home of the Grand National, and other leading tracks including Cheltenham.
She was appointed chairman of Aintree in 2014, having been a racecourse committee director there since 2005.
Sandy Dudgeon, senior steward of the Jockey Club, said: “This is tragic news and our thoughts go out to Rose’s husband, Owen, and all members of her family.
“Rose was a wonderful person and involved in so many aspects of our sport. She was a skilled chairman at Aintree, a valued member of our board of stewards and headed up our horse welfare group. She also enjoyed participating at grassroots level over many years.
“We appreciated her contribution very much and my fellow stewards and I looked forward to hearing her sound views on a subject, where she was always sensitive to the best course of action for racing. She will be missed greatly for the person she was.”
Her husband is MP for North Shropshire and a former Northern Ireland secretary.
“Owen rang me this morning to inform me that Rose had been found passed away at home,” said Steve Charmley, the chair of North Shropshire Conservative Association.
“Obviously, Owen is very devastated and asked to be left in peace to come to terms with the situation. Rose was a very well-liked person. “
In 2011, Rose joined her husband in a nine-day 1,000km (621-mile) race across Mongolia on horseback following a trail blazed by Genghis Khan.
They endured extreme weather, being set on by a pack of dogs, and she also survived two tumbles but raised more than £100,000 for charity.
British Horseracing Authority chief executive Nick Rust said he was “extremely saddened” by her death.
“Rose was one of those people who always seemed to see the bigger picture, do her best for the wider good and work tirelessly and selflessly towards achieving results,” he said.
“She also had the knack of being able to say the right words at the right time.”