Founded in 2001, Gray Horse Farm (GHF) brings a fresh perspective and approach to the competitive world of riding. Our training team, led by Erin Stewart, daughter of horse expert Don Stewart, and life-long horse expert Lauren Gridley, takes a disciplined yet caring approach to students of all ages. Whether you are new to the sport or experienced, GHF has something for everyone.
Operating out of the one of the premier riding facilities on Long Island, GHF offers lessons for aspiring hunters, jumpers and even polo players. The 115 acre farm is equipped with three outdoor rings, two indoor rings, a Grand Prix field as well as a polo field. All arenas are outfitted with top-of-the-line footing to ensure the best conditions in all weather. 

Ponies and horses are available for lessons, long-term leases and for sale. The team also travels to horse shows across Long-Island, the East Coast and Florida throughout the year. For our show schedule click here.

For young riders we also offer one of the top Pony Camps over the summer. In addition to lessons, riders will learn the ins-and-outs of horsemanship and care. For more information click here

We are open every day of the week, except Wednesdays, from 8 a.m. to 5 p.m. For more information, please call us at 561-358-6045 or 203-910-6297


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In 2001 with the help and support of my husband Mark, I left a rewarding career in marketing and opened Gray Horse Farm at our home in Upper Brookville. Our blended family included, Becky, five, Marissa, thirteen, and Daniel, nine. All of us working together, we restored the 1920’s brick barn, refurbished and expanded the old riding ring. Not too soon after, we added another barn and 4 more paddocks. When our Shetland pony named Coco and our semi-retired horse named Fairfield were safely stowed in their new stalls, we were ready for and optimistic about what would turn out to be the best twelve years of our lives.

When the children and I began competing we needed to upgrade our horse inventory. Soon we began importing special jumpers and hunters from Europe. It was fun, and challenging, and not always perfect, but my dream came true: happy children, good horses, and a dedicated trainer. We were blessed.

In 2009, the unthinkable happened. Mark was diagnosed with pancreatic cancer. Soon after the dreadful discovery he bought me my most treasured horse and I named her Halo. My husband died the next summer. Halo became my angel. I ride her in the adult jumper division and she has taken me safely from the starting tone to the last jump time after time. Halo watches over me at every jump. She gives her heart in every class and never lets me down, a faithful partner. Truly heaven sent.

Facing a new chapter in life, I decided to open a full- service stable in the Hamptons. When I drove up the dirt drive onto the old Clearview Farm on North Main Street in Southampton I knew this was it! In April 2012, I moved into a barn that needed a facelift by a woman who loves hard work. It was like starting anew. I cleaned, repaired, renovated and redecorated. I mended fences and planted gardens; painted the Pony Palace, mowed the tall grass, settled in the horses, blessed the grooms, said a prayer, and opened for business in May 2012.

Erin Stewart


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Erin RidingErin has spent her whole life among horse and is quickly establishing herself as the next generation of leading trainers on the East Coast. Daughter of expert trainer Don Stewart Jr., Erin started her tri-color collection in 1989 with a win in the lead line class at the Devon Horse Show. [XX] years’ later, Erin has successfully transformed from one of the top junior riders in the country to a Grand Prix competitor.  Career highlights include Gold Medalist in the Prix des States Team final at the Pennsylvania National Horse show, Leading Amateur Owner Rider at the CSI-W Washington International, USEF Horse of the Year, 1st at the ASPCA Maclay Final, and Best Child Rider at CSI-W Washington International and the Pennsylvania National Horse Show. 

Erin has trained with many top professionals such as Bibby Farmer-Hill, Bill Cooney, Michelle Grubb, Mark Leone, Leslie Burr-Howard, McLain Ward, Karen Healey and Emil Spadone. She decided to turn professional in 2010 and brings knowledge and experience from her junior and amateur years to the GHF team. 

Erin’s passion for the sport is in her blood and she has a natural eye for talented rider-horse combinations. She brings a steady and calming approach to the sport, making her relatable to riders of all ages. 

A full list of her impressive accomplishments include:

  • USEF Horse of the Year
  • Junior Hunter Grand Champion, CSI-W National Horse Show, NY
  • 3rd ASPCA Maclay Final, CSI-W National Horse show, NY
  • Best Child Rider, CSI-W Washington International, DC Junior Hunter Grand Champion, CSI-W Washington International, DC
  • Junior Hunter Grand Champion, Devon Horse Show, PA


  • 1st ASPCA Maclay Finals
  • USEF Horse of the Year
  • Junior Hunter Champion, National Horse Show
  • Best Child Rider, CSI-W Washington, DC
  • Junior Hunter Champion, CSI-W Washington, DC
  • 3rd WIHS equitation Finals, CSI-W Washington, DC
  • Best Child Rider, Pennsylvania National Horse Show, PA
  • Gold Medal Prix des States Team Final, Penn. National Horse Show, PA


  • 2nd NCHJA Welcome Stake, Raleigh, NC
  • 4th Grand Prix of Raleigh, Raleigh, NC
  • 1st High Amateur Owner Classic, Conyers, GA


  • 1st High Junior/Amateur Owner Classic, Cavalier Classic, Va
  • 2nd High Amateur Owner Classic, HITS Ocala, FL


  • 3rd Grand Prix, Palgrave, On


  • 3rd Ambassadors Cup, CSI-W Washington International, DC
  • Leading Amateur Owner Rider, CSI-W Washington International, DV


  • Top ten placings in Grand Prix competitions in California riding Devito


  • Circuit Champion Pre Green Hunter, HITS Thermal, CA
  • Numerous top finishes In Grand Prix events HITS Thermal,CA
  • Circuit Champion Pre Green Hunter, HITS Thermal, CA
  • Trained Lillie Keenan to junior hunter final grand champion on Confidential and Madison
  • Assistant trainer at Heritage to Lillie Keean and Vanhattan SJHR JR/AO Jumper classic at the National Horse Show


  • Assistant trainer at Don Stewart Stables to winner of USEF medal finals winner, Meg O'Mara and fourth place, Hasbrouck Donovan.


  • Developed young hunters and jumpers
  • Trained multiple junior hunter and jumper champions
  • Co-trained equitation champions
  • Top placings up to 1.45m
  • Top ten placings in national standard Grand Prix


  • Started a business in New York with ponies, hunters, jumpers, and equitation
  • Trained multiple pony champions
  • Trained Catherine Sullivan to High amateur owner jumper win in Fairfield

Erin Riding



Erin Stewart


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Erin Riding Lauren’s passion for horses started at an early age. Growing up on a farm in Connecticut, her family bred horses and she was determined to learn everything she could about horse care. Lauren quickly developed a knack for reading horses – understanding their likes and dislikes, quirks and needs. This knowledge became her secret weapon as she started to train and show her own horses. Competing in the hunters, jumpers and cross country, in addition to competitive polo, demanded that Lauren learn how to adapt, think quickly and prepare her horses thoroughly. Lauren’s diverse experience makes her one of the most knowledgeable and trusted trainers on the East End of Long Island. With a thoughtful and measured approach, Lauren is particularly good with young horses and riders. As she says, she “loves horses that are a ‘bit of a project.’ There is nothing more rewarding than seeing a horse and rider team come together and shine.”

Erin Riding



Erin Rivas


Erin Stewart
1 Hour Private $185
1/2 Hour Private $155
Non Boarding Clients includes school horse.
Annual Board $2,250
Monthly Board  
• October-May $2,250
• June-September $2,600
Sales Tax is charged on all board.
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Monthly Training (year round boarders) $750
Monthly Training (summer boarders) $850
Local $200
Away $200.00 per day when competing.
$125.00 per day non-competing days
• Housing and tack stalls shared by number of horses.
• Entries, initial bedding, braiding, professional rides, medications, and shipping will be billed at cost.
Body Clipping $175
Magnetic Blanket $50
• Stable Supplies shared by number of Horses.
• Outside lessons, professional rides and clinics at cost.


Pony Camp

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Sign up now to reserve your space for 2018

Camp Dates – June 18 – August 31
Monday – Friday (except Wed.), 9am – 1pm

•  Skilled & friendly trainers
• All levels of riders welcome
• 5 years and older
• After camp private lessons available

For more information call:
Download the registration form: Download Form
Pony Camp Pony Camp
Pony Camp Pony Camp

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