Located on a quiet dirt road just SE of Lake Creek is Lost Creek Covered Bridge. The following text comes from the NRHP nomination form:
The Lost Creek Bridge is the shortest bridge of all the Oregon covered bridges, at just 39 feet in length. The structure is located on a lightly traveled gravel road, an although still used daily, the bridge has an 8-ton load limit imposed.
Features of the bridge include the usual county queenpost truss design, daylighting by the use of slit windows above the truss tops, a shingle roof, and flying buttress braces. The bridge does not have the usual rounded portal designs at each end, having open ends. The rough, wooden flooring consists of diagonal planking. The hand-hewn truss members are notched and fitted with long bolts through the members, securing them tightly in place.
The bridge was nearly lost in the 1964 Christmas flood. As swirling waters and heavy debris lashed at its piers, residents and concerned bridge enthusiasts prayed during the night that the bridge be saved. According to a local newspaper, the skies opened and the water receded as morning came. The journalist questioned: Was the bridge saved by prayer?
Many Jackson County residents claim the Lost Creek Bridge to have been built as far back as 1874, making it the oldest covered bridge in Oregon. Historians, however, agree that the bridge was actually constructed in 1919.
To get there: From Medford, travel approx. 5 miles north on Hwy 62, turn east on Highway 140 for about 14 miles to the Lake Creek exit. From the exit, travel approx 5 miles to the bridge.
The flooring at the Lost Creek Bridge consists of planking laid in a diagonal pattern. Additional planks laid length-wise help to support the weight of passing traffic. The queenpost truss is modified by an "X" within the truss arrangement.
I also located a PDF document (link below) that reads:
The Lost Creek Bridge, at 39 feet, is the shortest of all Oregon covered bridges. Since 1979, the structure has been closed to traffic with a concrete span handling the few vehicles each day.
Many Jackson County residents, including Shirley Stone, daughter of pioneer John Walch, claim the Lost Creek Bridge to have been built as early as 1878-1881. If authenticated, this would make it Oregon's oldest standing covered bridge.
Johnny Miller, the builder of the Lost Creek Bridge, also roofed the nearby span at Lake Creek in the 1880s, thus lending credence to a sign nailed on the bridge: LOST CREEK BRIDGE, BUILT ABOUT 1881. The span may have been partially or totally rebuilt in 1919, hence the official construction date in that year.
Features of the bridge include the usual county Queenpost design, a shingle roof and flying buttress braces. The rough wooden flooring consists of diagonal planking, and hand hewn truss members provide structural stability. A new roof was installed by local residents in 1985. Portal boards were added in 1986, restoring the look of the span in 1920 before accommodations were made for log truck traffic.
The Walch Memorial Wayside Park abuts the bridge site. Descendants of John and Marie Newsome Walch built and maintain the park, which includes picnic tables, a bandstand, cooking areas, an early 1900s outhouse, and manicured flower gardens.
The bridge was nearly lost in the 1964 Christmas flood. As swirling waters and heavy debris lashed at its piers, residents and concerned bridge enthusiasts prayed during the night that the bridge would be saved. According to a local newspaper, the skies opened and the water receded as morning came. The journalist questioned, "Was the bridge
saved by prayer?"
(Reference: Roofs Over Rivers, by Bill and Nick Cockrell)
Features of the bridge include Queenpost trusses, a shingle roof and flying buttresses. The wooden flooring has diagonal planking.
The roof was replaced in 1985. In 1986 portal boards were added which restored the look of the span from changes originally made in 1920 to accommodate log truck traffic.
Wikipedia also make this superlative claim of the covered bridge being the shortest in Oregon here.