|This article relies largely or entirely upon a single source. (August 2013)|
|West end:||I-275 near Cincinnati, OH|
| US 23/Corr. C near Piketon, OH
I-77 near Parkersburg, WV
|East end:||I-79 near Clarksburg, WV|
In the United States, Corridor D is part of the Appalachian Development Highway System. It travels from Bridgeport, West Virginia to Cincinnati, Ohio. It travels US 50 for much of its eastern portion. The western portion of road in Ohio is known as State Route 32. ADHS Funding is separate from other Federal Highway funds.
The east end of Corridor D begins on US 50 between Clarksburg and Bridgeport, West Virginia, at Interstate 79. US 50 continues on its westerly heading toward Parkersburg and intersects Interstate 77 just outside downtown Parkersburg. The highway continues over the Ohio River on the Blennerhassett Island Bridge.
After crossing the Ohio River into Belpre, Ohio, the highway joins with State Route 32 and starts southwest for about 15 miles (24 km) then turns northwest for another 15 miles (24 km) reaching Athens. The combined US-50/OH-32 makes another turn southwest for about 12 miles (19 km). Then, US 50 and OH-32 diverge. US-50 begins heading west, OH-32, southwest. Corridor D follows OH-32 about 20 miles (32 km) to Jackson, where it is intersected by US-35. The highway heads due west for about 25 miles (40 km) and intersects US 23, Corridor C between Portsmouth and Chillicothe. OH-32 continues west for about 100 miles (160 km) into Cincinnati, crossing US-62, US-68 and Interstate 275, Cincinnati's beltway, in the process.
One of the original 23 corridors, Corridor D (U.S. Highway 50) was to provide access to major urban centers along the east coast from the midwest, while creating economic development for northwest and North-Central West Virginia and southeast Ohio.
The earliest segment of Corridor D, or US 50, to open in West Virginia was a six mile (10 km) segment in 1967  from an isolated point near Sherwood in Doddridge County (MP 15) to WV 23 in Salem in Harrison County (MP 1.52). Two years later, a segment from Salem east to CR 11 at Wolf Summit (MP 7) opened to traffic.
In 1970, major portions of Corridor D opened to traffic:
- A brief segment in Wood County from MP 8 to MP 11 near Murphytown.
- A lengthy segment in Wood County from WV 31 near Deerwalk (MP 15.41) to MP 4 at Nutter Farm in Ritchie County near North Bend State Park, a distance of seven miles (11 km).
- A segment of US 50 in Ritchie County at WV 74 at Pennsboro (MP 17) east to Doddridge County at West Union (MP 5.5).
Most of Corridor D opened a year later.
- A segment four-lane upgrade of US 50 opened in Wood County from Interstate 77 east of Parkersburg (MP 4) to MP 8 near Murphytown.
- A segment within Wood County from MP 11 near Murphytown to Sandhill (MP 15.41). This connected the disjointed segments between #1 and #2 listed above.
- The majority of Ritchie County's US 50 segment opened from MP 4 near North Bend State Park to WV 74 at Pennsboro (MP 17). This connected the disjointed segments between #2 and #3 listed above.
- A segment in Doddridge County from MP 5.52 near West Union east to WV 23 near Salem (MP 15).
In 1974, a segment of Corridor D in Harrison County opened to traffic from CR 11 at Wolf Summit (MP 7) to the CR 11 at Wilsonburg (MP 11). In 1977, this was extended eastward to WV 20 at Montpelier east of Clarksburg (MP 15.5), and a year later, to Interstate 79 west of Bridgeport (MP 18.25).
Completion into Ohio
Construction began in 2000 with the start of the Godbey Fields complex in Parkersburg, West Virginia. The $6.5 million 40-acre (160,000 m2) athletic complex was finished in 2001. Several contracts were let soon after, which included grading and drainage for part of Corridor D, a new Corning Glass Bridge for WV 47, and another span that would carry US 50 over WV 47 and 7th Street in Parkersburg.
On September 20, 2004, the second portion of Corridor D opened from WV 47 to WV 14, which included the construction of a Little Kanawha River crossing. With this segment open to traffic, 1/3 of the Parkersburg Corridor D segment was complete.
On March 9, 2005, a tied arch Ohio River crossing design was chosen from four designs as it was the "most economical and least intrusive on the environment of Blennerhassett Island. The $120 million eight-span bridge will include an 880-foot (270 m) tied arch over the main channel of the Ohio River and will stretch for 4,009 feet (1,222 m) from both abutments with a 69 feet (21 m) vertical clearance. It is being constructed from weathering steel and will connect WV 892 to OH 618. At the time of its contract letting in April 2005, it was the largest single highway contract in West Virginia's history. The bridge is expected to be complete in 2007.
On July 12, 2005, it was announced that the final Corridor D contract in West Virginia was to be awarded. This would complete paving and signing operations of 1.32 miles (2.12 km) from the WV 892, WV 95, and WV 68 interchange to River Hill Road. In Ohio, a single contract was announced that would connect the Ohio River span to U.S. Route 50 which would be completed in 2007.
In mid-September 2005, Corridor D was completed from Fifth Street in Parkersburg to WV 892, WV 95, and WV 68. This segment was constructed under five contracts and required the completion of ten bridges.
As of April 23, 2006, construction on the Corridor D mainlines from Interstate 77 to WV 892 is all but complete. The last segment, from WV 892 to the WV 892, WV 95, and WV 68 interchange, was slated to open in August.
On August 31, 2006, it was announced that from WV 892/WV 68 to the WV 892 interchange, Corridor D was open to traffic. This 1.32-mile (2.12 km) four-lane divided freeway is the final roadway section of the corridor from Clarksburg and Cincinnati without the Ohio River crossing.
The last Corridor D project, the Blennerhasset Bridge crossing the Ohio River, was opened on June 13, 2008.
- The official sign for Corridor D in West Virginia, while not utilized on full-sized shields, is a blue background shield with a West Virginia state outline in white with a blue letter in the center.
- In late 2006, there were recent additions of mile markers every 1/2 mile along Corridor D between Parkersburg and Clarksburg. These mile markers feature the official sign for Corridor D as described above.
- "Release Date Report". West Virginia Department of Transportation. August 2003.
- "New Godbey Fields under construction". West Virginia Department of Highways. April 25, 2000. Archived from the original on 2006-03-21. Retrieved August 25, 2013.
- "DOH Corridor D Briefing Set for October 25". West Virginia Department of Highways. October 19, 2000. Archived from the original on 2006-03-21. Retrieved August 25, 2013.
- "DOH to Open 1.9-Mile Segment of Corridor D". West Virginia Department of Highways. August 25, 2003. Archived from the original on 2008-07-06. Retrieved August 25, 2013.
- "Division Street of Corridor D Set to Open". West Virginia Department of Highways. September 15, 2004. Archived from the original on 2008-07-06. Retrieved August 25, 2013.
- "Island bridge bids opening March 1". West Virginia Department of Highways. March 28, 2005. Archived from the original on 2008-07-06. Retrieved August 25, 2013.
- Payne Jr., Dave (April 2005). "W.Va awards bridge contract". West Virginia Department of Highways. Archived from the original on 2008-07-06. Retrieved August 25, 2013.
- Bevins, Evan (May 2005). "Final Corridor D contract to be bid". West Virginia Department of Highways. Archived from the original on 2008-07-06. Retrieved August 25, 2013.
- Payne Jr., Dave (October 6, 2005). "New section of Corridor D to open next week". West Virginia Department of Highways. Archived from the original on 2008-07-06.
- Brown, William (April 23, 2006). "Corridor D continues to progress". West Virginia Department of Highways. Archived from the original on 2008-07-06. Retrieved August 26, 2013.
- "DOH to Open Final Roadway Section of Corridor D". West Virginia Department of Transportation. October 26, 2006. Archived from the original on 2007-09-26. Retrieved August 15, 2013.
- "Priority Average Composite Sheet1". (spreadsheet XLS). West Virginia Department of Transportation. November 1, 2006.[dead link]