Helen Ward of Richmond, Ky., has been a tour guide and club member for 20 years. She said the club, which has 42 members, strives to keep the tour as casual and meaningful as a private invitation. Buses are small, holding about 40 people each. Only one bus at a time will be allowed to stop at each of the farms. Often the owners take over the tour at their farms, Ward noted. "They are very proud of what they do and like to show it off," she said. "And they like being part of the community that makes Lexington so distinctive." Ward said this year's tour is especially interesting because it is so diverse.

Along with Walnut Hall, the tour stops at the American Saddle Horse Museum, which honors this Kentucky-created breed, and at Carriage Station Farm, where the horses - often thoroughbreds - are trained for jumping and dressage. Thoroughbred operations on the tour are Darby Dan Farm and Vinery. The tour guides also try to make the travel time educational, Ward said. For instance, she will talk about Iron Works Pike, where Walnut Hall is located. This road in the heart of horse country is an old route that originated as the way to get iron deposits in Bath County to the foundries in New Orleans. And, because at least half of the tour guests are new to the horse world, the guides always use travel time to be sure everybody knows horse lingo, said Ward. You will come away knowing the difference between a foal, a filly and a colt, and have some notion of the finer points of farm management.

Ward likes to quantify fencing, for instance. A four-board plank fence - the traditional horse fence - costs $16,500 per mile to build and paint the currently popular black. If you want your fence to be the traditional white, add $1,500 per mile. Not flush? Go for diamond mesh, "horse" wire with a black plank across the top. It's only $7,400 per mile. To put this into perspective, Calumet Farm has 23 miles of the traditional white fencing. Here are the tour stops.

Walnut Hall Ltd. Once a 3,000-acre parcel on North Elkhorn Creek, the farm emerged from the original 1777 land grant made by Virginia Gov. Patrick Henry to Col. William Christian, his brother-in-law. It became a prominent carriage stock farm when Lamon Harkness bought 400 acres of the land and the main house in 1892 and kept buying land, eventually making Walnut Hall a 3,700-acre farm in Fayette and Scott counties with another 1,400 acres farther west in Scott County. In 1972, nearly 1,000 acres of the land was purchased by the state of Kentucky to become the Kentucky Horse Park, and the original farm has been variously divided by family members. Vinery

Owner Ben Walden Jr. is a scion of a family of horsemen noted for having an eye for a good horse. Vinery horses include Real Quiet, winner of the 1998 Kentucky Derby; Victory Gallop, the second-place finisher sired at Vinery and trained by Ben Walden's brother, Elliott Walden; and Red Ransom, who commands a $50,000 stud fee. A recent partnership with George Hofmeister of Lexington has expanded the farm to include an Australian counterpart. The farm, established around 1810, operated for a time as Dearborn Farm. Carriage Station Farm

This 92-acre training-and-boarding facility specializes in eventing and includes a show-jumping arena and a small cross-country course. During the tour, farm instructor Cathy Wieschhoff, a Lexington native who is under consideration with her mare, Spelga Dam, for a spot on the U.S. Equestrian Team's Olympic squad, will be on hand to either ride or coach other riders. Visitors also can look through the barn, tack rooms and a well-appointed horse van used for long-distance travel to competitions.

Darby Dan Farm Once a part of the former 10,000-acre Idle Hour farm, today this stud farm with its crisp, white fences and white and green barns hung with baskets of red geraniums make a traditional picture of the older Bluegrass style. The farm is a Kentucky spinoff from the main farm near Columbus, Ohio. It is named for Darby Creek in Columbus and for Dan Galbreath, current owner and son of the founder, John Galbreath, who bought his Kentucky farm in the 1940s.

The American Saddle Horse Museum Trace the history of this Kentucky original, a cross of Morgan, thoroughbred and Tennessee walker much favored by farm owners and Army officers, through film and exhibitions. They disclose that Gen. Robert E. Lee's beloved Traveller was an early version of this cross-breeding. So was Mr. Ed and Fury of TV fame. Museum admission is included in the tour, which begins and ends at the museum.

If you go. . . The 28th Annual Open Horse Farm Tour, sponsored by the Suburban Woman's Club of Lexington, begins and ends at the American Saddle Horse Museum at the Kentucky Horse Park, north of Lexington on Iron Works Pike at Exit 120 off Interstate 75. Parking is free to tour guests, $2 for other horse park visitors. Tour buses depart between 8:30 a.m. and 1 p.m. tomorrow and Sunday for the four-hour tour. Buses leave as they fill, generally on the half-hour. Tickets are $25.

Food is available at the rest stop at Vinery farm. For more information, or to be sure the tour is not sold out, call (606) 223-9082. A foal and mare stuck close together near the foaling barn at Walnut Hall Ltd. farm.