The County Antrim town on Belfast Lough that most people mean is Carrickfergus , a coastal town on the northern shore of Belfast Lough in County Antrim, Northern Ireland.

What the clue points to

  • Belfast Lough has two main coastal towns: Bangor on the southern (County Down) shore and Carrickfergus on the northern (County Antrim) shore.
  • Because the question specifies a County Antrim town on Belfast Lough , that eliminates Bangor and leaves Carrickfergus as the matching town.

Quick facts about Carrickfergus

  • Historic port and commuter town lying on the north shore of Belfast Lough in County Antrim.
  • Widely known for Carrickfergus Castle , one of the best‑preserved medieval castles in Ireland, guarding the lough’s shoreline.

Answer: Carrickfergus.