This is an annotated transcription of the Rev. Dr. James Muir's personal diary from 1805. Born in Ayrshire, Scotland in 1757, Rev. Muir served as the third minister of the Presbyterian Church in Alexandria, Virginia, now known as the Old Presbyterian Meeting House, from 1789 until his death in 1820. The Old Presbyterian Meeting House was originally known as Alexandria's Presbyterian Church and then as its First Presbyterian Church. Rev. Muir's diary provides a historical document that, in its account of a single calendar year in the life of one individual, both raises and answers questions about a bygone era. It also provides a historical guide to aspects of the remarkable heritage that continues to this day in Old Town Alexandria, Virginia; a heritage that exists today in the vibrant religious community of the Old Presbyterian Meeting House and in the larger community, where the streets that Muir walked, and so many of the houses and places he visited still exist. A discussion of Alexandria in 1805, an examination of the original diary and its transcription, and a biographical sketch of Rev. Muir precede the diary. Appendices include: the diary's title page and handwritten notes that appear on end pages of the diary, a list of the Bible texts of sermons by Rev. Dr. Muir during 1805 (in the order delivered), and a list of the published works of the Rev. Muir. A bibliography and an index to full-names, places and subjects enhance the text.