Kentucky supplemental roads and rural secondary highways are the lesser two of the four functional classes of highways constructed and maintained by the Kentucky Transportation Cabinet, the state-level agency that constructs and maintains highways in Kentucky. The agency splits its inventory of state highway mileage into four categories: The State Primary System includes Interstate Highways, Parkways, and other long-distance highways of statewide importance that connect the state's major cities, including much of the courses of Kentucky's U.S. Highways. The State Secondary System includes highways of regional importance that connect the state's smaller urban centers, including those county seats not served by the state primary system. The Rural Secondary System includes highways of local importance, such as farm-to-market roads and urban collectors. Supplemental Roads are the set of highways not in the first three systems, including frontage roads, bypassed portions of other state highways, and rural roads that only serve their immediate area.
The same-numbered highway can comprise sections of road under different categories. This list contains descriptions of Supplemental Roads and highways in the Rural Secondary System numbered 3000 to 3499 that do not have portions within the State Primary and State Secondary systems.
KY 3019
Kentucky Route 3019 is a rural secondary highway in southern Edmonson County. The highway begins at KY 101 (Chalybeate Road) south of Rhoda. KY 3019 follows Chalybeate Road north across Beaverdam Creek, a tributary of the Green River, into the village of Rhoda. The highway intersects Brownsville Road in the village and follows that road across a branch of Beaverdam Creek to its northern terminus at KY 259 (Veterans Memorial Highway) north of Rhoda. The Kentucky Transportation Cabinet established KY 3019 along the bypassed portion of KY 101 and part of the bypassed portion of KY 259 through Rhoda via a September 23, 2002, official order after the latter highway was relocated around Rhoda. The agency transferred Brownsville Road between KY 3019 and the KY 101–KY 259 intersection to county maintenance through the same official order.
KY 3021
Kentucky Route 3021 is a rural secondary highway in central Edmonson County. The highway begins at KY 259 (Veterans Memorial Highway) north of Rhoda. KY 3021 heads north along Brownsville Road, which crosses a branch of Beaverdam Creek, a tributary of the Green River. The highway enters the city of Brownsville and ends at KY 259 (Main Street) south of downtown. The Kentucky Transportation Cabinet established KY 3021 along the bypassed portion of KY 259 south of Brownsville through a September 23, 2002, official order after the latter highway was relocated between Rhoda and Brownsville.
KY 3057
Kentucky Route 3057 is a urban secondary highway in the city of Somerset in Pulaski County. The south–north highway begins at KY 914 and travels north before terminating at KY 1247 .
KY 3064
Kentucky Route 3064 is a one-way supplemental road in the city of Louisville in Jefferson County. KY 3064 is a one-way westbound highway that begins at US 150 and runs westbound along Portland Avenue then Northwestern Parkway before ending at KY 3216, which is a one-way northbound highway and therefore has no access to from KY 3064. From KY 3216, it continues westward as Northwestern Parkway.
Major intersections
KY 3067
Kentucky Route 3067 is a rural secondary road that begins from U.S. Route 60 (US 60) following Booth Field Road. The road heads up north to the ending of state maintenance at the Ben Hawes Park.
KY 3069
Kentucky Route 3069 is a supplemental road in the city of Louisville in Jefferson County. The highway begins at a dead end at a Kentucky Transportation Cabinet maintenance garage in an industrial area next to an R.J. Corman Railroad Group–Norfolk Southern Railway rail line east of the I-65–I-264 interchange near Louisville International Airport. KY 3069 follows Sanita Road east to an intersection with KY 864 (Poplar Level Road) and Gardner Lane at the city limit boundary between Louisville and Watterson Park south of KY 864's interchange with I-264 (Watterson Expressway).
KY 3078
Kentucky Route 3078 is a supplemental road in the city of Louisville in Jefferson County. KY 3078 begins at KY 1065 (Outer Loop) and the western terminus of KY 3079 and travels eastward along the north side of KY 1065 and ends at the eastern terminus of KY 3080.