This dissertation presents a dialectological study of the city of Erie, Pennsylvania, and the neighboring towns in the boundary area between the North and Midland dialect regions. The field work conducted for this dissertation consists of interviews, word lists, minimal pair tests, and grammatical acceptability judgments. In total, data from 106 speakers was analyzed to determine the course of linguistic change in the city of Erie and the current location of the dialect boundaries in the neighboring regions. In order to process the acoustic data from this large corpus, the methodology of transcription and subsequent forced alignment was applied. In order to reduce error in the formant measurements, automatic techniques for measurement point selection and formant prediction were developed. The acoustic analysis focuses on aspects of the vowel system that differentiate the North and the Midland. The results show that the merger of /o/ and /oh/ began in the city of Erie before 1900, and that it subsequently spread to Ripley, NY. On the other hand, Erie is still located on the Northern side of the boundary with respect to the fronting of the back upgliding vowels /uw/, /ow/, and /aw/. Finally, an analysis of the lexical and morphosyntactic variables shows a widespread acceptability of the Midland features in Erie. In the final section of the dissertation, the early settlement history of the region is examined, and Erie's acceptance of several Midland features is explained by the early presence of a large contingent of non-Northern, especially Scots-Irish, settlers.