Senegal is a coastal West African nation located 14 degrees north of the Equator and 14 degrees west of the Prime Meridian. The country's total area is 196 190 km² of which 192 000 km² is land and 4 190 km² is water, making the nation slightly smaller than Britain or the U.S. state of South Dakota.

Senegal is bordered to the west by the North Atlantic Ocean. On land, the nation's longest border is with Mauritania to the north, an 813 km border along the Senegal River. To the east is the 419 km border with Mali. In the southeast is Guinea (330 km border) and to the southsouthwest is Guinea-Bissau (338 km), both borders running along the Casamance River. Senegal is one of only a handful of countries to have a near-enclave within its borders—the small nation of The Gambia in the interior, which has a 740 km border with Senegal. The Gambia penetrates more than 320 km into Senegal, from the Atlantic coast to the center of Senegal along the Gambia River, which bisects Senegal's territory. In total, Senegal has 2 640 km of land borders, and 531 km of coastline and shoreline. Senegal makes maritime claims of a 24 nmi (44.4 km; 27.6 mi) contiguous zone, a 12 nmi (22.2 km; 13.8 mi) territorial sea, and a 370 km (200 nmi; 230 mi) exclusive economic zone. It also claims a 200 nmi (370.4 km; 230.2 mi) continental shelf, or to the edge of the continental margin.

The lowest point in Senegal is the Atlantic Ocean, at sea level. The highest point is an unnamed feature near Nepen Diakha in the Fouta Djallon foothills at 581 m (1,906 ft)).