This essay aims to shed light on the prevalence of the to + adverb + verb and to not + verb split infinitives in American English, both in a historical perspective and in present day usage, and how it varies in different contexts where different levels of formality are expected. Although students are taught to avoid splitting constructions, numerous grammarians and linguists question this prescriptive viewpoint. Two extensive corpora, the Corpus of Historical American English (COHA) and the Corpus of Contemporary American English (COCA), were used to gather data. The results revealed how the frequency of the split infinitive was, and still is, rising rapidly, and becoming more and more a standard and accepted feature in American English. The most common context in which to find a split infinitive was that of informal spoken language. However, it was in the most formal of settings, that of academic texts, where the largest increase in prevalence of the split infinitive was seen.