Police called to the property in St George's Hill, Weybridge, at about 10:00 BST by ambulance crews also found a man in his 30s with serious injuries.
Formal identification has not yet taken place, Surrey Police said.
St George's Hill is a private, gated estate with a golf club and tennis club, where six-bedroom homes are listed for about £14m.
Det Ch Insp Jason Taylor said officers believed they knew the identity of the woman and the man, who was taken to hospital for treatment.
He said next-of-kin had been informed.
"The investigation into this tragic incident is still in the very early stages but at this time I believe this to be an isolated incident,"  the detective said.
The 964-acre estate is described by the St George's Hill Residents' Association as having been "designed for driven, motivated and successful high achievers".

Alana Annette Savell, 32, was hosting a couple at her Panama City home when the visitors apparently became noisy.
Police say she ordered them to go, before shooting the man and woman in the legs. The victims went to hospital with non life-threatening injuries.
Ms Savell has been charged with aggravated battery by a firearm.
Bay County Sheriff's Office told the BBC the female victim had turned up with a male friend, whom she had just met in a bar, at the accused's home at around 01:00 local time on Monday.
Ms Savell told police her hospitality began to wear thin after her guests began drinking and raising their voices.
But instead of dropping a hint by yawning or loading the dishwasher, she armed herself with a 22-calibre handgun and shot at her guests' feet, officials said.
As well as shooting the woman, Kristy Jo Mohr, in both legs in the incident, and her companion, who went by name "Cowboy", Ms Savell's own boyfriend was struck by a bullet in the leg.
Ms Mohr told police she believed eight or nine shots were fired in total.
Bay County Sheriff's Office said: "The victim (Ms Mohr) stated she felt herself get hit in the legs and ran away from the home and got into a vehicle.
"Savell stated that the victim and her friend had come to her home to hang out and began drinking and getting too loud.
"Savell stated she did not want them in her house and started shooting at their feet.
"The suspect's boyfriend stated to investigators that he has told his girlfriend that once someone is told to leave their property three times, she is to go get the gun and shoot it at the ground.
"If that does not work, she is to shoot people in the leg."
Ms Savell remains in custody at the county jail.
A murder inquiry is under way after the body of a woman in her 30s was found at a house in an exclusive part of Surrey.
[NEXT_CONCEPT]
A Florida woman opened fire on her house guests because they were "too loud" and had overstayed their welcome, police say.