Pleasanton is a city in Alameda County, California, incorporated in 1894. It is a suburb in the San Francisco Bay Area located about 25 miles (40 km) east of Oakland, and 6 miles (9.7 km) west of Livermore. The population was 70,285 at the 2010 census. In 2005 and 2007, Pleasanton was ranked the wealthiest middle-sized city in the United States by the Census Bureau.
Pleasanton is located at 37°40′21″N 121°52′57″W / 37.67250°N 121.88250°W / 37.67250; -121.88250 (37.672530, -121.882517) and is adjacent to Hayward, Livermore, and Dublin. According to the United States Census Bureau, the city has a total area of 24.3 square miles (63 km2), of which, 24.1 square miles (62 km2) of it is land and 0.2 square miles (0.52 km2) of it (0.63%) is water. On the east side of town on Stanley Boulevard near the Livermore border is Shadow Cliffs Regional Park, a lake that holds swimming, fishing, boating, and a waterslide. On the west side is the Pleasanton Ridge with the two parks Pleasanton Ridge and Augustin Bernal Park. Much of Pleasanton is drained by the Arroyo del Valle and Arroyo Mocho watercourses. Pleasanton lies along the route of the historic First Transcontinental Railroad.