Morristown High School in 1950. It’s now Morristown East.
Anyway, I was puzzled about this picture. The inventory number, lower right on the front, dates this card to 1950; however, the primary source for information on this school (Wikipedia) gives a date 1955 for the addition of that 3rd floor. Sounded kind of wrong to me, because the building looks to be fully developed as it. Then, I ran across this picture . The school was built in 1923 and that black-and-white image is from the ’30s. Maybe there was a 3rd story added somewhere, but I don’t think it was here. Btw, Morristown High School is the oldest accredited high school in Tennessee.
The card was published by Blackburn News Agency in Kingsport, but it’s a Genuine Curteich-Chicago “C.T. Art-Colortone” post card (Reg. U.S. Pat. Off.). It’s in fairly good shape, despite the staining on the back.