The 20-year-old spent the last two seasons on loan at Torquay, scoring 16 goals in their National League South promotion campaign in 2018-19 but failed to make much impression in the National League (English Fifth tier) last term.
According to NewsChain, County manager Michael Flynn told the club’s website that he has been closely watching Janneh for the last few seasons and wanted him to join the club in January.
“Saikou is someone who I feel can enjoy a successful season and hopefully this club can play a big role in his development, he said.”
Saikou Janneh added: “The manager really wanted me to come here and he likes the way that I play. I learned a lot playing in the National League with Torquay last season and I think it has prepared me for League Two.
“I want to come to this club, work hard and score as many goals as possible. I can’t wait for the new season to get underway.”
The 21 years old was on target for County in a convincing victory for the Exiles against
Hereford United on Saturday.