State Route 140 (SR 140) is a state highway in the U.S. state of California, 102 miles (164 km) in length. It begins in the San Joaquin Valley at Interstate 5 near Gustine, and runs east into the Sierra Nevada, terminating in Yosemite National Park.

In June 2006, the road between El Portal and Mariposa was closed due to a rock slide. The Ferguson Slide buried about 600 feet (180 m) of SR140 between Cedar Lodge and Briceburg Visitor Center between SR-49 and SR-41.

Though a detour opened in August, 2006, those anticipating travel between Mariposa and El Portal (Yosemite National Park) on SR140 are still advised to contact the National Park Service, California Highway Patrol, Caltrans, or the Mariposa County Sheriff to find out if the road is open.

SR 140 is part of the California Freeway and Expressway System and is eligible for the State Scenic Highway System. However, only the part of the road from Mariposa to El Portal is designated as a scenic highway.

Heading east from I-5, the highway passes Gustine; it then jogs to cross the San Joaquin River. It roughly marks the southern edge of the farmable land around Livingston. It crosses State Route 99 at Merced. Visitors who travel from the Bay Area or northern California to Yosemite Valley or the southern portion of Yosemite will transfer from Highway 99 to Highway 140 at this point. (Those who visit the northern portion of Yosemite would have taken either State Route 120 east at Manteca, or State Route 132 east at Modesto.)

The highway continues through Planada, after which the farmland gives way to grazing land. It is quite dry in the summer due to California's Mediterranean climate, and the dry grass gives the landscape a golden color. Western meadowlarks, American kestrels, red-tailed hawks and turkey vultures are frequently glimpsed. A few blue oaks can be seen as the highway leaves the valley and begins to climb through the foothills of the Sierra Nevada. They become more and more numerous as the elevation increases. As the highway passes through Catheys Valley the vegetation begins to diversify a little. California live oaks and ponderosa pines intermingle with the blue oaks as it nears Mariposa.

A ponderosa pine forest borders the highway on both sides as it passes through Midpines. As it approaches Briceburg, the roadway follows a steep, winding grade down to the Merced River valley. The highway then runs alongside the Merced River for 20 miles to the park entrance, after passing through El Portal before finally entering Yosemite Valley, where it ends.

Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, and do not necessarily reflect current mileage. The numbers reset at county lines; the start and end postmiles in each county are given in the county column.