This abandoned tower is located on Forest Service land just outside of Georgetown. It looks like it hasn't been used in a very long time.
Many of the towers and rough roads to them were built by the CCCs (Civilian Conservation Corps) created by President Roosevelt in the Great Depression.
Early communication took place by telephone, carrier pigeon, and a machine that sent Morse Code signals by flashes of light.
I climbed a few of these towers when I was a kid and when I was in college the Forest Service recruited for summer "fire lookouts" on campus. I looked into it but took a job at a scout camp instead. As I remember, the pay would have been a lot better but the jobs were out west and transportation was a problem.
There are many fire towers still in use today, manned by humans using technology a bit more sophisticated than carrier pigeons, I imagine.
The Forest Service also rents out unmanned towers during the summer for about $40 a night. Be prepared to hike in (and up!) carrying your own water, equipment, and supplies!
This one in Oregon looks pretty inviting to me.