St. Johnsbury (sometimes locally known as "St. Jay") is the shire town (county seat) of Caledonia County, Vermont, United States. The population was 7,603 at the 2010 census. St. Johnsbury is located approximately northwest of the Connecticut River and south of the Canadian border.
St. Johnsbury is the largest town by population in the Northeast Kingdom and serves as a commercial center for the area. In 2006, the town was named "Best Small Town" in National Geographic Adventure's "Where to live and play" feature. The more densely settled southern half of the town is defined by the U.S. Census Bureau as a census-designated place (CDP), where over 81% of the population resides.
The town was originally granted in 1760 as part of the New Hampshire Grants and named Bessborough. It was regranted by Vermont in 1786 as Dunmore, and settled the same year. An early settler was Jonathan Arnold, a member of the Continental Congress and author of Rhode Island's act of secession from the United Kingdom in May 1776. Arnold left Rhode Island in 1787 and, with six other families, built homes at what is now the town center.
In the mid-19th century, St. Johnsbury became a minor manufacturing center, with the main products being scales — the platform scale was invented there by Thaddeus Fairbanks in 1830 — and maple syrup and related products. With the coming of the railroad line from Boston to Montreal in the 1850s, St. Johnsbury grew quickly and was named the shire town (county seat) in 1856, replacing Danville. The oldest occupied residence in St. Johnsbury was built in 1801 and is located on Clarks Avenue.
The former St. Johnsbury Fairgrounds were located where Interstates 91 and 93 converge, south of the town. The Third Vermont Regiment drilled there prior to joining the Union Army during the Civil War.
The first air flight in Vermont occurred at the fair on September 24, 1910.
In the 1940s the city contained three major industries. Each was the largest in the world. One was Fairbanks Scales, another was a maple sugar candy company, a third made candlepins for bowling. The rest of the economy was mostly rural.