Preserving large farming landscapes is one of the main goals of farmland preservation programs. Other goals include protecting highly productive soils, maintaining and enhancing the local farming economy, and promoting locally produced fresh food. Farmland preservation programs take time, however, because of the hefty funding requirements and the detailed process of preserving farmland through the acquisition of conservation easements by purchase or donation. The standard measures of dollars spent and farmland acres preserved do not give an accurate picture of the spatial outcomes of preservation and preservation effectiveness. Three other measures better reflect the spatial effectiveness of farmland preservation: acreage and percentage of preserved farm parcels located in agricultural zones, number and acreage of preserved farm parcels in large contiguous blocks, and number and acreage of preserved farm parcels along growth boundaries. Scattered preserved farms and preserved farms not located in agricultural zones are likely to face more nonfarm development nearby as well as problems with non- farm neighbors. The farmland preservation effort in Lancaster County, Pennsylvania, provides an important case study of the pattern of farmland preservation over time. Other counties and land trusts can employ geographic information systems (GIS) methods in this study to monitor and evalu- ate the progress of their farmland preservation efforts.