The geography of the legal profession and legal culture, and the possibility that there were major regional differences in the use of law and legal institutions across historic Europe have been little studied by historians. This article compares England and Wales with Scotland, whose private law was different, and Ireland, where English common law worked alongside indigenous law traditions. Lawyers can be divided between those who pleaded and those who prepared documents, but the nomenclature and professional development of ‘men of law’ differed considerably within the component parts of Britain and Ireland. The article brings out these differences and, in so doing, hopes to provide a framework for comparing the place of the legal profession and the use of law over space and time. It is in two parts. The first explores the changing numbers of different sorts of legal practitioner in England and Wales, Scotland, and Ireland: barristers, solicitors/attorneys, advocates, writers, and notaries. From an early date, England and Wales had many more lawyers per head of population than other parts of what became the United Kingdom of Great Britain and Ireland; the legal profession was dominated by attorneys, who far outnumbered barristers, whereas in Scotland and Ireland those who pleaded formed a significant proportion of all men of law. The second part seeks to explain this difference, by examining how different societies related to the formal practices of law and to alternative forms of dispute resolution. The component parts of the British Isles had distinctive social structures, economic compositions, religious emphases, and cultural forms, which meant that the place of law and lawyers in their societies varied considerably. The argument is that, as well as having different legal institutions and professional structures, Scottish and Irish people used the law more selectively than their English (and perhaps also Welsh) equivalents.