Ulster differs from the other three historical provinces of Ireland in the presence of Ulster Scots, an off-shoot of Lowland Scots brought principally from the Western and Central Lowlands of Scotland in the 17th century through a plantation established by King James I and through periodic migrations, especially in times of economic duress in Scotland. Since that time Ulster Scots has been spoken in rural parts of Counties Antrim, Donegal, Down, and Londonderry/Derry, where it was mapped by Robert Gregg in the 1960s mainly on the basis of phonological features. The present article, based on eight years of fieldwork with native speakers in Antrim, analyzes a range of pronominal, verbal, and syntactic features, seeking to identify general patterns as well as variation within Ulster Scots. When possible, comparisons are made to Lowland Scots and Irish English in order to situate structural features of Ulster Scots within the larger linguistic landscape of the British Isles.