Alexander Bache U.S. Coast Survey Line

Alexander Bache U.S. Coast Survey Line is a historic geodetic survey line located at Edisto Island, Charleston County, South Carolina. This base line was surveyed by Alexander Dallas Bache and his assistants during January 1850 as part of their work with the United States Coast Survey. They buried granite blocks at each endpoint and then placed a granite monument on top of each block.

It was listed on the National Register of Historic Places in 2007.