Confederate forces acquired hundreds of Clyde-built boats because they were fast, making them ideal for evading Union ships blockading Southern ports.
Archaeologists believe the shipwreck off Oak Island, North Carolina, is a blockade runner called Agnes E Fry.
It was launched on the Clyde under a different name, Fox.
A sonar scan was made of the wreck earlier this year and the shape, size and location suggests that it is of the Agnes E Fry.
Deputy state archaeologist, Billy Ray Morris, told the BBC News Scotland website that a further investigation was imminent.
He said: "We will be conducting 3D sonar imaging operations on Fry next week and will have a detailed computer model of the site shortly thereafter."
The North Carolina archaeologist added: "Agnes E Fry was built by Caird & Co in Greenock. She was launched 26 March 1864.
"She was an iron-hulled paddle steamer with two oscillating engines. She was lost 27 December 1864 commanded by Joseph Fry.
"Originally named Fox, Fry renamed her after his wife when he took command."
Coincidently, work is also under way to try and give a wrecked blockade runner in Scottish waters better protection.
The Iona I operated on a Glasgow to the Highlands passenger route before it was purchased by Confederate agents for use in delivering supplies to blockaded American ports.
But it never reached the war as it sank in the Clyde near Gourock following a collision with another ship in 1862.
Earlier this year, the Scottish government proposed designating the site as a Historic Marine Protected Area (HMPA) to preserve it as a historic asset of national importance.
Historic Environment Scotland has begun a public consultation on the designation.
The wreck of Iona I has been described as being in a good condition. Glasgow Museums has a scale model of the paddle streamer in its collections.
Archaeologists are preparing to make a detailed examination of a wreck believed to be that of a Scottish ship used in the American Civil War.