The Old Plank Road is a plank road in Imperial County, California, that was built in 1915 as an east–west route over the Algodones Dunes. It effectively connected the extreme lower section of Southern California to Arizona and provided the last link in a commercial route between San Diego and Yuma.

A plank road is a road composed of wooden planks or puncheon logs, as an efficient technology for traversing soft, marshy, or otherwise difficult ground. Plank roads were commonly found in the Canadian province of Ontario as well as the Northeast and Midwest of the United States in the first half of the 19th century. They were often built by turnpike companies.