Lafayette (formerly, La Fayette) is a city in Contra Costa County, California, United States. As of 2011, the city’s population was estimated to be 24,285. Today Lafayette is known for its wealthy inhabitants and pastoral rolling hills. The town is also known for excellent schools within the highly ranked Acalanes School District. In 2012, estimated median household income in Lafayette was over 150,000 dollars, more than double the statewide average and nearly triple the national average.

Lafayette is located at 37°53′09″N 122°07′05″W. According to the United States Census Bureau, the city has a total area of 15.4 square miles (40 km²). 15.2 square miles (39 km²) of it is land and 0.2 square miles (0.52 km²) of it (1.08%) is water.

The city is part of the greater San Francisco Bay Area and has its own station on the BART public transit system. Lafayette is situated between Walnut Creek, Moraga, and Orinda, and, together with the latter two towns, is considered locally as part of “Lamorinda”.

Lafayette is separated from greater Berkeley and Oakland by the Berkeley Hills (and the Caldecott Tunnel running beneath), a geographical boundary within the East Bay which also represents interesting meteorological, cultural, and political distinctions. Like the rest of the San Francisco Bay Area, Lafayette has a Mediterranean climate (Köppen climate classification Csa); however, the climate differences can be striking: during the summer, temperatures can soar beyond 100 °F (38 °C) in Lafayette and its neighboring cities while the areas west of the hills and nearer to the bay remain up to 20 degrees cooler. Summers are warm, dry and very sunny (although mornings can be foggy); winters are cool and damp, with occasional freezes. Most of the annual rainfall comes in the winter, although there are still plenty of clear days during that time. The record high temperature is 115 °F (46 °C), set in July 1972. The record low temperature is 19 °F (−7 °C), set in December 1990. The region directly east of the hills is generally known for its more suburban or rural atmosphere, and features rolling, grassy hills which highlight a more peaceful and domestic aura. In the southwestern part of Lafayette, is the Lafayette Reservoir, and Briones Regional Park extends into the northern part of Lafayette. Lafayette’s wildlife communities include mixed woods and oak woodlands.