After two months using Fort Smith as the base for his botanizing and exploring, Nuttall left the garrison on July 6. He continued traveling upstream on the Arkansas River with the Three Forks area his next goal. He arrived there on July 14.
“Three Forks” refers to where the Verdigris and Grand Rivers enter the Arkansas very close to each other. Nuttall says they were only 1/4 mile apart; on a current map it looks like about 3/4 mile. Whereas Fort Smith was a brand new fort in 1819, Three Forks was a landmark and trade routes node of long standing. There were four trading posts in operation when Nuttall arrived.
Barry Bruton and I are going to explore the Three Forks area this weekend.