[3] Between the castle and village sits Plas Llanstephan, Lord Kylsant's former residence, which is also a grade II* listed building [4] Llansteffan Castle, built by the Normans in the 12th century and granted to the Marmion family, stands above the village on a promontory commanding the estuary passage.

Located between the ferry crossing-points of the Tywi and Tâf rivers, Llansteffan was an important staging post on the coastal route from Glamorgan via Kidwelly to Pembroke.

In 2018, a ferry service resumed using an amphibious boat to negotiate Llansteffan beach by Carmarthen Bay Ferries using a customized Sealegs Amphibious Craft offering 5-10 minute crossings to Llansteffan and 45 minute estuary and 1 hour trips, having received a grant of £300,000 from the Coastal Communities Fund.

The grant had been applied for by a former resident of the community, Professor Kenton Morgan and local reactions to the service and the culture of grantsmanship was covered in a BBC Radio 4 programme.

This ward stretched north from Llansteffan to include Llangynog and Llangain, with a total population of 2,006.