top of page

 About us 

Founder Richard Mills


Millhaven Horse Farm was founded by Richard Mills. Richard was a Maryland native who grew up riding and for 30 years, was an avid fox hunter.


He established his first boarding barn in 1968. In 1985, he bought the Derwood property and established Millhaven Horse Farm. Richard prided himself on keeping a well-maintained farm. The standards he established are maintained today by the farm's manager and staff.  


Diana Delmar is a long-time horse owner. A resident of the farm for over 20 years and Richard's "significant other," she has overseen horse health care and in 2021, took over farm management after Richard's death.  


She's also a science editor and writer specializing in veterinary medicine and is the author of "Taking Up Riding As An Adult" as well as two dog care books. (See link at bottom of page for more information on her horse book). 

 24/7 care, all the time

Horses on the farm vary widely in age and breed. Each is treated as an individual. 

Diana's home is built in the barn, over the stalls and the staff lives on the property. We all have considerable experience caring for horses of all ages as well as retirees and post-op patients. 

Relaxed, non-competitive atmosphere


We are an adult barn and the atmosphere at Millhaven is relaxed for boarders and horses. You'll find a friendly, eclectic group of riders. Most ride English and some Western. Many are interested in dressage, some are hunter/jumpers and there are a few eventers. Virtually everyone at Millhaven likes to ride primarily for fun and everyone's primary concern is really good horse care. 

For more information on Taking Up Riding As An Adult, click here.


Reader reviews of Taking Up Riding as an Adult from 


"Excellent and helpful. This book is well worth the price. It provides an excellent overview to the entire equestrian sport... The author has excellent knowledge of the sport and command of the English language. This book is great for any adult looking to take up the sport or parent seeking to better understand his/her child's passion." 


"Great Introduction to Riding. I'm 43, and I bought this book after I'd been riding for a year, because I wanted to go over the basics again and make sure that I was doing things right... I especially like the way the author stresses safety... This is a great little book, and I recommend it to any adult who's new to riding or thinking about learning how to ride."

bottom of page