Glen Mills is an unincorporated community in Chester County and Delaware County, PA. Glen Mills is about 17 miles west of Philadelphia.

The area around Glen Mills was part of the original land grant given to William Penn in 1681. George Cheyney was the first settler here, for which the nearby town of Cheyney is named.

The name Glen Mills is taken from two paper mills built by the Willcox family, one in 1835 and the second in 1846. From 1864 to 1878, these mills supplied the United States government with a special, patented paper for the printing of government bonds and notes.