N4 road (Senegal)
The N4 road is the Trans-Gambia Highway extension in Senegal, which is the main connection between the Casamance in the south and Dakar. It runs S/N from Ziguinchor to Bignona. It crosses the Gambia between Soma and Farafenni. You can reach Dakar via Kaolack.
An alternative (smaller) route is N5 via Bignona and Banjul.