Until World War II, Montgomery County's economy and landscape were primarily agricultural. American Indian tribes grew corn, squash, and beans in villages near streams. The earliest settlers from Europe raised tobacco for profit on small farms and large plantations, often with enslaved labor. In the 18th and 19th century, local agricultural reformers encouraged the county's residents to diversify from tobacco into grains, fruits, and vegetables. Dairy farming became possible with the arrival of the railroad in 1873, and trains carried fresh milk from Montgomery County creameries to nearby Washington, D.C. In the second half of the 20th century, growing suburbanization increased development pressure on the county. In 1980, community organizers, the Montgomery County Planning Board, and the County Council helped create the Agricultural Reserve by setting aside more than one-third of the county's land for agricultural use. The reserve encompasses 93,000 acres along the county's northern and western borders, protects more than 500 farms, contributes millions of dollars to the county's annual economy, and preserves open fields and agricultural landscapes in an area close to the nation's capital.