Samantha wrote:

Does anyone know where the first radio station was located in the
United States?! Thank you!!

http://www.tvhandbook.com/History/History_radio.htm

RCA's 'Radio Central' xmitters went on-line 1921 here on Long Island. I
remember them taking the last 410' tower down in '77. The buildings
still stand but are not used for anything. At 5200 acres it is the
largest undisturbed plot of land on the island.
HTH