COVERED BRIDGES evoke charm, history and the romance of the American landscape. In the late 1800s, more than 20,000 of them spanned the creeks and rivers of the country; now, fewer than 880 of these curious structures remain, making them great subjects for travel brochures and tours. Luckily, Washington area residents only have to journey to Frederick County -- not as far as the Madison County (Iowa) of book and movie fame.

"Of the five remaining covered bridges in Maryland, three are in Frederick County," says Dean Fitzgerald of the Frederick County Covered Bridge Preservation Society. According to Fitzgerald, each of the three wooden bridges is unique and structurally interesting, and the beauty of touring them is that they are within 12 miles of one another, making for an ideal afternoon outing or even a scenic bicycle trip.

But before you pack the picnic and get out the camera, take this quick covered bridge quiz: Why were covered bridges covered? If you answered, "to protect the wood construction of the bridge from rotting," you answered right. That the bridges also served nicely to protect people and animals in bad weather was just an additional benefit. At the end of the 19th century, iron and steel became cheaper, and construction shifted to these longer-lasting materials, signaling the obsolescence of the quaint wooden bridges.

Their bulky red shapes and dim, musty interiors notwithstanding, the covered bridges of Frederick are still very much in use at their north county locations. At Loy's Station Bridge near Thurmont, the banging of cars on the wood planks of the 90-foot-long, one-lane structure blends with the happy squeals of children playing in the water below. Originally built about 1848, Loy's Station spans the cool, gentle waters of Owens Creek, which forms an ideal swimming hole almost directly under the barn-red bridge.

Loy's Station Bridge is the focal point of a small county park complete with playground, picnic pavilions and the irresistible lure of the creek. Kathy Stick, a day-care provider in Frederick, likes to bring her young charges there on special occasions during the summer. "The kids love to build dams and play in the creek," Stick says. "They love the bridge. It's one of their favorite places."

The bridge's design uses multiple king post trusses (the side panels with diagonal braces) covered with beveled clapboarding, and had to be rebuilt after an arsonist's fire nearly destroyed it in 1991.

Materials from the original bridge were used whenever possible, and you can still see some of the charred timbers. The names on some of the roof shingles inside the bridge are new, however. After the bridge burned, the Covered Bridge Preservation Society raised funds to help rebuild the bridge, collecting $1 per name. Within 10 days of the fire, the society had sold 2,503 names.

At a length of only 40 feet, Roddy Road Bridge is the smallest of Frederick County's covered bridges. Located north of Thurmont not far from Route 15, this bridge also crosses Owens Creek and was probably constructed between 1856 and 1861. There's a small recreational area with a few parking spots, so visitors can get out, check out the bridge and enjoy watching the creek rushing under the stone abutments.

The bridge's truss system -- this is what supports a bridge -- is a single king post truss. At only 12 feet high, Roddy Road Bridge was damaged in 1992 by an oversize truck. Preservation society members, other volunteers and county staff worked to get the bridge reopened quickly. Fitzgerald, who owns a sawmill, even custom-cut some of the new wood beams.

Perhaps the Frederick County covered bridge with the most intriguing past is Utica Bridge, which spans Fishing Creek just west of the hamlet of Utica. This bridge uses a Burr arch truss design and dates to 1850 or possibly earlier. Originally, Utica Bridge was half of a longer span that crossed the nearby Monocacy River; in 1889, the storm that caused the Johnstown, Pa., flood washed it out, along with many other area bridges. Residents reconstructed it with whatever parts they could find and placed it across Fishing Creek.

Park where you can, and, after watching for traffic, be sure to check out the dusky interior of the 101-foot-long covered bridge. The Burr arch is clearly visible, as are many notches that seem to be out of place: These are from the mismatched bits and pieces used when the bridge was rebuilt. If you look carefully, you can still see the remnants of several 19th-century advertisements high up in the beams.

THE COVERED BRIDGES OF FREDERICK COUNTY -- The best way to locate the bridges is to first stop at the Tourism Council of Frederick County, 19 E. Church St., Frederick, and pick up an area map and driving directions. You can also get bridge information on its Web site, www.fredericktourism.org, or call 800-999-3613. Open daily from 9 to 5. All three bridges are east of Route 15 and north of Frederick in the vicinity of Thurmont: Utica Bridge on Utica Road, just off Old Frederick Road; Loy's Station Bridge on Old Frederick Road, just south of Route 77; and Roddy Road Bridge at Roddy Road and Roddy Creek Road, just north of Thurmont. Please note: Use caution if you choose to walk onto the bridges. There are no lights or walkways inside them, and motorists may drive onto the bridge without seeing you. Always have another person look for vehicles, and be prepared to exit the bridge quickly.

Liam Coates, from left, Katie Levine, Eliane Coates and Louis Levine wade in Owens Creek near Loy's Station Bridge near Thurmont in Frederick County, which has three of Maryland's five covered bridges.