Land owners in the rural Midwest experienced significant capital gains during the late 1840s and early 1850s. A primary catalyst of increasing land values was the construction of new railroads. Land in close proximity to new railroads became more valuable because of decreased transportation costs. We use a straightforward model of land price determination to estimate the impact on land values of distance from the railroad. The estimates allow us to infer a lower bound for capital gains attributable to the construction of railroads in Knox County, Illinois, during the 1850s. Knox County landowners reaped capital gains of more than $270,000—9% of the value of land.