<Li> Pharr spur--Mexican Federal Highway 40 from Monterrey to Reynosa, Tamaulipas </Li> <Li> Brownsville spur--Mexican Federal Highway 101 from Ciudad Victoria to Matamoros, Tamaulipas </Li> <P> From Mexico City to the border with Guatemala, the highway follows Mexican Federal Highway 190 . </P> <P> The Pan-American (or Inter-American) highway passes through the Central American countries with the highway designation of CA - 1 (Central American Highway 1). In Guatemala, it passes through 10 departments, including The Department Of Guatemala, where it passes through Guatemala City . In El Salvador, it passes through the cities of Santa Ana, Santa Tecla, Antiguo Cuscatlán, San Salvador, San Martín, San Miguel, and crosses the border into Honduras at Amatillo . From Honduras, it passes into Nicaragua, passing though the Nicaraguan cities of Chinandega, Estelí, Sebaco Matagalpa, León, and Managua, before entering Costa Rica at Peñas Blancas . In Costa Rica, it passes through Liberia, San José, Cartago, Pérez Zeledón, Palmares, Neily, before crossing into Panama at Paso Canoas . In Panama, it crosses the Panama Canal via the Centennial Bridge, and ends at Yaviza, at the edge of the Darién Gap . The road had formerly ended at Cañita, Panama, 110 miles (180 km) north of its current end . United States government funding was particularly significant to complete the high - level Bridge of the Americas over the Panama Canal, during the years when the canal was administered by the United States . </P>

Why does the pan american highway stop in panama