John Smith Phelps was a politician and soldier during the American Civil War, and the 23rd Governor of Missouri.

Phelps County is a county in the central portion of the U.S. state of Missouri. As of the 2020 United States Census, the population was 44,638. The largest city and county seat is Rolla. The county was organized on November 13, 1857, and was named for U.S. Representative and Governor of Missouri John Smith Phelps.