County Londonderry in the context of "Counties of Northern Ireland"

The Plantation of Ulster (Irish: Plandáil Uladh; Ulster Scots: Plantin o Ulstèr) was the organised colonisation (plantation) of Ulster – a province of Ireland – by people from Great Britain during the reign of King James VI and I.

Small privately funded plantations by wealthy landowners began in 1606, while the official plantation began in 1609. Most of the land had been confiscated from the native Gaelic chiefs, several of whom had fled Ireland for mainland Europe in 1607 following the Nine Years' War against English rule. The official plantation comprised an estimated half a million acres (2,000 km) of arable land in counties Armagh, Cavan, Fermanagh, Tyrone, Donegal, and Londonderry. Land in counties Antrim, Down, and Monaghan was privately colonised with the king's support.

Ulster (/ˈʌlstər/; Irish: Ulaidh [ˈʊlˠiː, ˈʊlˠə] or Cúige Uladh [ˌkuːɟə ˈʊlˠə, - ˈʊlˠuː]; Ulster Scots: Ulstèr or Ulster) is one of the four historical provinces of Ireland, located in the northern part of the island. It is made up of nine counties, with six of these comprising Northern Ireland (a part of the United Kingdom), while the remaining three are in the Republic of Ireland.

It is the second-largest (after Munster) and second-most populous (after Leinster) of Ireland's four traditional provinces, with Belfast being its biggest city. Unlike the other provinces, Ulster has a high percentage of Protestants, making up almost half of its population. English is the main language and Ulster English the main dialect. A minority also speak Irish, and there are Gaeltachtaí (Irish-speaking regions) in County Donegal which is home to a quarter of the total Gaeltacht population of the Republic of Ireland. There are also large Irish-speaking networks in southern County Londonderry and in the Gaeltacht Quarter, Belfast. Ulster-Scots is also spoken extensively in the counties Antrim, Down, Londonderry, Tyrone and Donegal. Lough Neagh, in the east, is the largest lake in the British Isles, while Lough Erne in the west is one of its largest lake networks. The main mountain ranges are the Mournes, Sperrins, Blue Stack (Croaghgorms) and Derryveagh Mountains.

Lough Foyle, sometimes Loch Foyle (Irish: Loch Feabhail, meaning 'Feabhal's loch' or "loch of the lip"), is the estuary of the River Foyle, on the north coast of Ireland. It lies between County Londonderry in Northern Ireland and County Donegal in the Republic of Ireland. Sovereignty over the waters has been in dispute since the partition of Ireland and the establishment of the Irish Free State in December 1922.

Derry, officially Londonderry, is the second-largest city in Northern Ireland. Located in County Londonderry, the city now covers both banks of the River Foyle. Cityside and the old walled city being on the west bank and Waterside on the east, with two road bridges and one footbridge crossing the river in-between.

The population of the city was 85,279 in the 2021 census, while the Derry Urban Area had a population of 105,066 in 2011. The district administered by Derry City and Strabane District Council contains both Londonderry Port and City of Derry Airport. Derry is close to the border with County Donegal, with which it has had a close link for many centuries. The person traditionally seen as the founder of the original Derry is Saint Colmcille, a holy man from Tír Chonaill, the old name for almost all of modern County Donegal, of which the west bank of the Foyle was a part before 1610.

The Sperrins or Sperrin Mountains (Irish: Sliabh Speirín) are a mountain range in Northern Ireland. The range stretches from Strabane and Mullaghcarn in the west, to Slieve Gallion and the Glenshane Pass in the east, in the counties of Tyrone and Londonderry. The landscape is mostly moorland and blanket bog. The region has a population of some 150,000 and is a designated Area of Outstanding Natural Beauty.

The River Foyle (from Irish An Feabhal) is a river in west Ulster in the northwest of the island of Ireland, which flows from the confluence of the rivers Finn and Mourne at the towns of Lifford in County Donegal, Republic of Ireland, and Strabane in County Tyrone, Northern Ireland. From here it flows to the city of Derry, where it discharges into Lough Foyle and, ultimately, the Atlantic Ocean. The total length of the River Foyle is 32 km (20 mi). The river separates part of County Donegal from parts of both County Londonderry and County Tyrone. The district of County Donegal that borders the western bank of the River Foyle is traditionally known as the Laggan. This district includes the villages of St Johnston and Carrigans, both of which are nestled on the banks of the River.