A lot line is the legal boundary separating one property from adjacent properties or public areas like roads and lanes. Lot lines define exactly where one person's land ends and another's begins, established through surveys and registered in the land titles system. Municipal zoning bylaws require buildings to be set back minimum distances from lot lines, protecting privacy, ensuring adequate light and air, and maintaining consistent neighbourhood character. Disputes over lot line locations are resolved through professional surveys. Understanding lot lines matters when planning construction, installing fences, or addressing issues with neighbouring properties.