This post card can certainly be dated as being 109 years old today. The post mark tells us that it was mailed on July 1, 1909. But, it is older than that. This type of post card was used for mailing post cards prior to March 1, 1907. Prior to this date, one could only write the message on the front of the post card. The back was reserved for the address only.
The front of the post card is showing the American Falls in the Snake River http://www.onlyinyourstate.com/idaho/id-underwater-ghost-town/