Today, northern New Jersey, the lower Hudson Valley and Long Island lie within the most densely populated corridor of land in the United States. In the early nineteenth century small towns, forests, farms and gardens populated this bucolic landscape. In the 1820s New York City's ascendance as the most important port and largest city in the United States changed this situation forever. This dissertation charts that transformation, and focuses on a single aspect: the story of how rapid urban expansion influenced agriculture and farm life in sixteen counties surrounding and including Manhattan Island. Commercial expansion encouraged population growth, first only in Manhattan, but later in neighboring Brooklyn and Newark. Together these three cities exerted a profound, but limited influence on agriculture and farm life;Chapter One focuses on the historiography of peri-urban agriculture and the nature of urban expansion in the New York City region. It provides a framework for interpreting the various responses of agrarian men and women to the sudden growth of the metropolis, in terms of farming systems. Chapter Two seeks to evaluate the direct economic effects of urbanization by examining agricultural production, property values, probate records and land tenure patterns. Of interest are the ways farm families took advantage of new opportunities by selling and developing their land, and leasing it to tenants. Chapters Three and Four are concerned with urban influences on markets. Chapter Three focuses on retailing, including farm gate sales, peddling and transactions made at the public markets. Chapter Four deals with agrarian wholesaling, characterized by trade with country stores and city merchants. Chapters Five through Eight take the reader through each of the four seasons of the "agricultural year." Of importance in this section are agrarian attitudes toward technology. In this era of "improvement" agriculturists selected new labor-saving technologies with care, which earned them the scorn of the progressive farming movement. Chapter 9 looks backward from the vantage point of 1870 and concludes that although the new metropolis definitely shaped agriculture and farm life, the seasonality of agrarian life remained strong.