Dating Postcard Eras
- Note: Some of the dates are circa, meaning they may vary a few years one way or the other. We give more specific information on these dates and eras in the Postcard Publishing Eras in this section. The dates listed below are useful and apply to most postcards. We did not list the Pioneer Era, pre-1898, because we do not have any Yellowstone postals as examples. However, this is another era of postals that predate PMCs.