The township, which lies in the western half of Philadelphia's Main Line suburbs, comprises predominantly parts of two unincorporated areas: Devon and Berwyn.

The township is believed to have been incorporated in 1704 since that is the earliest date it has been found to be referred to in official records.

[3] Whilst the originators of the Welsh Tract were Quakers, the earliest settlers in the portion that became Easttown Township were mostly Anglicans.

Revolutionary War leader Anthony Wayne was born and lived in Waynesborough house, in the western part of the township.

[5] Two sites in the township are listed on the National Register of Historic Places: Waynesborough and Roughwood.

[6][7] Easttown Township is said to have the most-litigated zoning law in Pennsylvania, largely as a result of its efforts to avoid being swallowed up by the expansion of the suburbs of Philadelphia.

At least two major cases about minimum lot size were handed down by the Pennsylvania Supreme Court: Bilbar Construction[8] upheld the township's minimum lot sizes, while National Land and Investment Co.[9] struck them down as 'exclusionary' seven years later.

National Land further held that a municipality may utilize zoning measures that are substantially related to the protection and preservation of the municipality's proper interest in providing for the general welfare of its residents, but Easttown's zoning did not pass the test.

Ironically, despite the developer-litigants' claimed interest in allowing poor people to live in Easttown, they built only houses that sold at well over the average value in Pennsylvania.

According to the United States Census Bureau, the township has a total area of 8.2 square miles (21 km2), of which 0.12% is water.

[14] Students residing within township boundaries attend Conestoga High School for grades 9-12.

Series creator Brad Ingelsby was born and raised in Berwyn, which is partially located in Easttown Township.