The function of the semicolon has changed considerably since the 15th century, from primarily indicating the length of a pause, to providing syntactic information. According to prescriptive grammar, the semicolon is used to join independent clauses and to avoid complexity by separating items in a list. Still, there is limited descriptive data on how the semicolon is used, a gap addressed by this study. Based on data from the Corpus of Historical American English, 1,600 semicolons from four different written genres from 1920–2019 were analysed, and their functions were classified. The overall results show that the frequency of semicolons has decreased considerably, most notably in Fiction. It is argued that sentences are becoming shorter and simpler, and that semicolons are primarily associated with more formal genres. Still, from the 1970s, semicolons have been used extensively to separate short segments in lists, especially in printed advertisements. This is possibly the last bastion of the semicolon. Furthermore, the results indicate that the semicolon has been increasingly used in accordance with prescriptive punctuation rules. A possible explanation is that most studied texts were written by professional writers, and that people who doubt their ability to use semicolons simply refrain from using them. Nonetheless, when the semicolon is used in a non-standard way, it is often used in the place of a comma, producing a sentence fragment. Since the colon and the semicolon carry somewhat overlapping functions, further descriptive comparisons of the two could yield important findings. It is also suggested that this research is supplemented by further qualitative studies to capture the rationale behind the use of semicolons in different situations. That could assist educators in explaining punctuation practice to make language users comfortable in using the full potential of punctuation marks.