Folarin Balogun leaves Arsenal to join Monaco
The 22-year-old has not played for the Gunners in a competitive match since netting 21 goals in 37 Ligue 1 appearances for Reims last term.
According to a source at the principality club, Monaco paid an initial transfer fee of 30 million euros (£25.8 million) which could rise to 40 million euros (£34.4 million).
Balogun will undergo a medical before being presented to the press on Thursday.
Despite scoring seven goals in 13 appearances for England's Under-21 team, the New York-born Balogun switched international allegiance to the United States.
He netted his first international goal in the USA's CONCACAF Nations League final victory over Canada in June.
Balogun came through Arsenal's academy but only played 10 matches in all competitions for the club.
"We thank Folarin for his contribution to Arsenal, through our academy into the first team, and wish him the best of health and happiness in his new chapter at Monaco," an Arsenal statement said.
Monaco lead the early Ligue 1 table with seven points after scoring 10 goals across their first three games.