There are over 700 public charging stations in the DC & Baltimore area! See map below.
Federal workplace charging: several federal facilities have charging stations available for personal use.
This map is courtesy of PlugShare, a crowd-sourced application where people can add, review and comment on public and private charging stations.
Some public charging stations may require use of an RFID card which is obtained by opening an account with the charging station network provider. Most stations are free to use, but some stations charge fees of up to $2.50 / hour.
The most popular charging station networks in the DC / Baltimore area are: