Located in the northwestern part of the county, it borders the following townships: No municipalities are located in Radnor Township, although the unincorporated community of Radnor lies at the center of the township.

The name Radnor is derived from Radnorshire, Wales, the native land of a first settler.

[5] The township is governed by a three-member board of trustees, who are elected in November of odd-numbered years to a four-year term beginning on the following January 1.

There is also an elected township fiscal officer,[6] who serves a four-year term beginning on April 1 of the year after the election, which is held in November of the year before the presidential election.

Emergency medical services in Radnor Township are provided by the Delaware County EMS.