Round barns in the United States date back to the late 18th century although their popularity did not rise until the 1880's. The first round barn was designed by George Washington in 1793. It was a 16-sided threshing barn built at his farm near Mount Vernon. The first true round barn was built by a Shaker community in Hancock, Massachusetts in 1826.
The origins of the round barn design are a bit harder to trace. Washington may have based his design the English custom of putting a roof over the horses walking in a circle to provide power to mills. It is said that the Quaker round barns may have been based on neighboring Indian wigwams. It could also have been that the Shakers based their design on the sacred circle, symbolizing eternal life. By the 1880's round barns were being touted by agricultural land grant colleges who taught progessive farming methods. The round barns remained popular well into the 1920's.
The agriculture colleges promoted round barns for a several reasons. First, the circle form has a greater surface to volume ratio than the traditional rectangular form, thus fewer materials were needed to build it. The efficiency also applied to the roofs which were self supporting, thus enlarging the amount of storage space on the upper level. The round barn was also said to withstand windstorms better.The milking process was more efficient when the cows all faced the center, allowing the farmer to move in a continuous direction. As advances were made in silo construction, they were placed in the center of the barn and gravity could be used to feed the cattle from a central source.
In the early twentieth century, as agriculture was moving beyond subsistence farming and mechanization was advancing, the round barn lost its popularity. Today, thousands of round barns are still standing in the United States, although many are being lost each year to wind, weather, and neglect. Maintaining these barns has become too costly for many, so they are often torn down. Luckily, many owners are keeping their barns in good form, and nonprofits are stepping up to preserve hundreds of others. Many have been placed on the National Register of Historic Places
The majority of round barns in the United States were built in the Midwest, although there are round barns as far west as California. Ohio, Indiana, Wisconsin, Iowa, and Minnesota are home to numerous round barns.