The fraudsters, whose total number has not been disclosed, were busted in a joint operation by Ghanaian police and the US embassy.
They are reportedly cooperating with officials who are investigating the extent of their scam.
The gang sought clients from Ghana and neighbouring West African countries, and brought them to a building in Accra where the American flag was flown.
For a fee of $6,000 (£4,700), the unsuspecting applicants were issued visas which were not all fake, suggesting the involvement of insiders at the American consulate.
The people reportedly arrested by the police are of Ghanaian and Turkish nationalities.
The scam has gone on for this long because the victims have never been to an embassy - they are mostly from rural areas and they seemed to be reassured by the presence of what appeared to them to be white people at the fake embassy.
One more reason why the gang operated successfully for this long was the fact that some of the visas were genuine - and those who travelled to the US unwittingly advertised the fake embassy through word of mouth.