Long Vale House, previously called Clonfade, sits on the outskirts of Porthall on the R265 road to Lifford. Parts of it were built in 1611 - making it one of the oldest houses in County Donegal. The builder, Thomas Keyes, had served under Sir Richard Hansard during the Plantation of Ulster, and when Hansard was appointed Governor of Lifford he gave Keyes a plot of land at Clonfade to build a house on. Keyes went on to become High Sheriff of Londonderry City in 1623. Four centuries later, the house is now known as The Hall Green. About four kilometres north of Porthall, the ruined Mongevlin Castle stands on the west bank of the Foyle. In the sixteenth century it was the chief residence of Ineen Dubh, daughter of MacDonnell, Lord of the Isles, and mother of Red Hugh O'Donnell - the warrior chieftain who led the resistance against the Tudor conquest of Ulster. A state paper recorded her as O'Donnell's mother dwelling at Bunaber. Captain Nicholas Pynnar surveyed the rebuilt castle in 1619.

James II - the last Catholic king of England, Scotland, and Ireland - visited Mongevlin Castle on his way to the siege of Derry in 1689. The siege would last 105 days and end in failure for James, but on the night he stopped at Mongevlin he still believed the Jacobite cause might prevail. From the castle he sent a letter to Derry proposing surrender. The defenders rejected it. Within months James would lose at the Boyne, the Glorious Revolution would consolidate the Williamite settlement, and the entire political geography of Ireland would shift. The castle eventually passed to The Hon. Elizabeth Hamilton, whose eldest son James, Earl of Abercorn and Viscount Strabane, erected a memorial plaque to her in 1704. The castle is now mostly ruined, with only fragments still standing. The flagstone that once carried the inscription J.S.-E.S.T.-1619 over the archway disappeared in the early 18th century. The history disappears piece by piece into the boggy ground of the Foyle valley.

Two and a half miles northwest of Porthall, at the summit of a hill called Binnion, the Battle of Binnion Hill was fought in 1557. The story is the same one passed down in Porthall's local history as if the village had a stake in it - because in a sense it does. Calvagh O'Donnell, surprise-attacking John O'Neill's camp on the shore of Lough Swilly after consulting his imprisoned father, killed many of O'Neill's men and captured eighty horses including Shane O'Neill's stallion The Son of the Eagle. O'Neill escaped through the rain with two companions, swimming the swollen rivers Deele, Finn, and Derg. The booty was the largest of any battle between the two great Gaelic dynasties of the northwest. Today the hilltop is quiet pasture. The river runs the same banks. The houses in Porthall stand on the same bones.

Porthall railway station opened on 1 May 1848 as part of the Great Northern Railway of Ireland, on the line that ran from Belfast Great Victoria Street through Portadown, Dungannon, Omagh, Victoria Bridge, Strabane, Porthall, and St Johnston to Foyle Road station in Derry City. Goods trains stopped on 4 January 1965. The line and station closed permanently on 15 February that year - part of the wave of railway closures across rural Ireland that left whole communities cut off from the network that had defined them since Victorian times. The nearest working station now is across the border at Derry-Londonderry. The current population of Porthall, recorded at the 2011 census, was 253 people - 130 men and 123 women. The houses face the Foyle as they have for centuries. The horse that drowned in Calvagh's spoils, the king who lost Derry from a castle four kilometres away, the Nuremberg lawyer who later owned the Georgian house - they all share the same small piece of east Donegal earth.