I am still on vacation and will not return to my work on 2nd January 2018, I do have a question about locating old Aerial Photos that I am seeking for my project. I am going to work on a lot of old not georeferenced aerial photos on my forest boundary. I have them that are on my external hard drive. If, for some reason, one or several aerial photo might be missing. I need to pull one or a few to be include my project. I am aware that USGS EarthExplorer and several other site that carry aerial photos that you can download from the internet.
My question to you is does the public or private library potential might have them on their online or in their storage ?
If the city or county offices has them, which department do they most likely have them ?
I prefer them to be free and download only. I am looking at the aerial photos that are done pre-50's.