The original Carmarthenshire Dock was built by Alexander Raby in 1899 and carried his name. It changed name when it was updated as part of the Carmarthenshire Tramroad in 1802.
Its use declined with the fortunes of the railway but was the main site of local ship building in the mid century when the slip was built on the north side.
The Harbour Trust took it over in 1842 and in the following year they diverted the river Lliedi from Old Castle Road through a new cut to scour the dock.
The slip can be seen under a slab of concrete and the dock is generally neglected.