Atglen is a borough in Chester County, Pennsylvania, United States. According to the 2020 census, its population is 1,311.
Present-day Atglen was originally a wilderness where Native Americans made paths that cut across this area when they traveled from Paxtang in present day Harrisburg to present day New Castle, Delaware to trade with the Swedes and later the English. The Great Minquas Path was one of these trails.
In 1717, Sadsbury Township was organized. It covered a large territory, including in whole or in part the present-day townships of Sadsbury, West Sadsbury, West Caln, Valley, East Fallowfield, West Fallowfield, and Highland; the boroughs of Atglen, Parkesburg, Modena, and South Coatesville; the city of Coatesville; and parts of Lancaster County. In August 1728, several inhabitants petitioned the court to separate Sadsbury from Fallowfield because of the former's size. In November of that year, the township was subdivided into East a