The city shares a 15-mile (24 km) border with Mexico that includes two border crossings. San Diego hosts the busiest international border crossing in the world, in <answer>the San Ysidro neighborhood at the San Ysidro Port of Entry</answer>. A second, primarily commercial border crossing operates in the Otay Mesa area; it is the largest commercial crossing on the California-Baja California border and handles the third-highest volume of trucks and dollar value of trade among all United States-Mexico land crossings.
Where is San Diego's border crossing?
the San Ysidro neighborhood at the San Ysidro Port of Entry