The Wiliam H. Natcher Green River Parkway is a limited-access freeway from Bowling Green to Owensboro in the US state of Kentucky. The Natcher is one of nine highways that are part of Kentucky's parkway system. Conceived as the "Owensboro–Bowling Green Parkway," it was instead named the Green River Parkway when it opened on December 15, 1972. It received its current name in 1994 following the death of the late William H. Natcher, a United States Congressman who represented the Second District of Kentucky for three decades. Natcher is best known for his record-setting string of 18,401 roll call votes, even being wheeled in on a hospital gurney to vote shortly before his death.

The Natcher Parkway was a toll road from its opening until November 21, 2006.

In 2006, the old and new names were combined into the current name, in order to be consistent with most of the Commonwealth's other parkways, all of which had their original names changed in the same manner to honor various Kentucky politicians. However, the newly-designed marker signs that were installed on the Natcher Parkway in the summer of 2006 do not bear the words "Green River."

The parkway begins at an interchange with US Route 231 (US 231) south of Interstate 65 (I-65, exit 20) near Bowling Green. It travels along the west side of the city in a northwesterly direction, through rolling farmlands and near coal mines, for 70.24 miles (113.04 km) before meeting its northern terminus at an interchange with US Highway 60 Bypass (US 60 Byp.) at Owensboro. At exit 41, the parkway intersects with the Wendell H. Ford Western Kentucky Parkway, the longest and oldest road in the state's parkway system. The Natcher Parkway bypasses the cities of Morgantown, Beaver Dam and Hartford. The parkway carries the unsigned designation of Kentucky Route 9007 (WN 9007).

On November 21, 2006, toll plazas on the Natcher were removed. Prior to their removal, toll plazas were located at Exit 7/Bowling Green (through cars 50 cents), Exit 34/Morgantown (40 cents), and Exit 48/Hartford (60 cents). Motorists travelling between the I-65 exit and Exit 7 in the Bowling Green area were not charged toll.

The Natcher and the nearby Audubon Parkway, were the last two roads in the Kentucky parkway system to have their tolls removed. Under Kentucky law, toll roads cease toll collection once their construction bonds are paid, either by collected tolls or other sources.

The parkway was designated a part of the "Future Interstate 66 Corridor," a proposed four-lane Interstate utilizing the existing Cumberland and Hal Rogers parkways, among other routes, across the southern tier of Kentucky. It cannot be signed as an Interstate until it has permanent connections to the east and west, both of which have not been determined because the King Coal Highway in West Virginia was demoted to a corridor-standard roadway for US 52.

All or part of the Natcher from the Western Kentucky Parkway interchange southward has been proposed to become part of the controversial proposed extension of I-66 through Kentucky. Exactly how much of the southernmost 41 miles (66 km) of the highway will be used has not yet been decided—various plans call for the route to diverge from the Natcher somewhere north of Bowling Green and head east toward I-65, forming a northern beltline around the city; another plan would have I-66 follow the Natcher route all the way to the current I-65 interchange, then turn north and overlap I-65 to its junction with the Cumberland Parkway.

Natcher Parkway is to become an Interstate spur. Jeff Moore, chief of the division of planning for the state Department of Highways, said in an interview with The Daily News in Bowling Green that Kentucky is studying a new north–south corridor through the state, I-69. While the major portion of the road would be in western Kentucky, a spur for the newly designated roadway could have its terminus in Bowling Green. It would use the William H. Natcher Parkway between Bowling Green and Owensboro.

I-69 is well on its way to becoming another major north–south Interstate in Kentucky as parkway upgrade studies are complete. A 55.3-mile (89.0 km) section was established as I-69 on September 30, 2011, from Madisonville west to Calvert City on I-24. I-69 red, white, and blue Interstate signs were to be installed on the section of freeway in October 2011. As for I-66, "Interest has been lost in the I-66 project," Moore said

The new I-69 corridor wouldn’t necessarily funnel traffic away from I-65 and Bowling Green. Moore said it could actually bring traffic here with the Interstate spur designation of the Natcher Parkway from Owensboro to Bowling Green. The parkways that would be added to the Interstate System would be studied and then brought up to Interstate standards where needed. The study will consider widening shoulders, lengthening exit and entrance ramps, ensuring clearance heights under bridges for wide and tall loads and, in some instances, widening the travel lanes.

Preliminary recommendations from the studies will be sometime next year (2012). Improvements, Moore said, will be recommended in “small bites.”