, the San Joaquin River watershed had a human population of roughly 4,039,000, about 1.9 million of whom live within the section of the watershed not including the Tulare Basin. The largest cities are Bakersfield, near the south end of the valley on the Kern River; Fresno, roughly in the geographic center; Modesto, on the Tuolumne River; and Stockton, on the southeast fringe of the Delta region. Other major cities include Visalia, Tulare, Hanford, Porterville, Madera, Merced, Turlock, Manteca and Lodi. Population growth is among the highest in the state of California and more than twice the U.S. average. In Madera County, near the geographic middle of the basin, growth was 51.5% between 1990 and 2003, the highest in the San Joaquin basin. Most of the major cities lie on the State Route 99 corridor, which runs along the entirety of the San Joaquin Valley and forms the primary thoroughfare for the valley. Interstate 5 provides the major transportation route for the west side of the valley.