Located at the northeast end of the Cumberland Basin, an arm of the Bay of Fundy, Amherst is strategically situated on the eastern boundary of the Tantramar Marshes 3 kilometres east of the interprovincial border with New Brunswick and 65 kilometres east of the city of Moncton. It is also located 60 kilometres southwest of the New Brunswick abutment of the Confederation Bridge to Prince Edward Island at Cape Jourimain.
Amherst is the shire town and largest population centre in Cumberland County. According to Dr. Graham P. Hennessey, "The Micmac name was Nemcheboogwek meaning "going up rising ground", in reference to the higher land to the east of the Tantramar Marshes. The Acadians who settled here as early as 1672 called the village Les Planches. It was named Amherst by Colonel Joseph Morse, the first settler, in honour of Lord Amherst, the commander-in-chief of the British Army in North America during the Seven Years' War.