Lake Merced, Freshwater lake in San Francisco, United States

Lake Merced is a natural freshwater lake in southwest San Francisco, fed by an underground spring. It has an irregular shoreline with a wide lobe and narrow inlets, and its dark blue-green water is bordered by reeds and low vegetation. It is one of the city's three natural freshwater lakes, alongside Pine Lake and Mountain Lake.

Lake Merced is a natural freshwater lake, named Laguna de Nuestra Señora de la Merced by Captain Bruno de Heceta in 1775. In 1868 the Spring Valley Water Company bought its water rights, and the lake was long planned as San Francisco's main reservoir before the 1908 approval of O'Shaughnessy Dam. On September 13, 1859, David S. Terry killed David C. Broderick in a duel at the lake.

The lake lies in San Francisco's southwest corner, bordered by the Olympic Club, San Francisco Golf Club and TPC Harding Park. Paths along the shore are used for walking and running. The California Office of Environmental Health Hazard Assessment has issued a safe-eating advisory for fish caught here because of mercury levels.

The area is home to a variety of birds and other wildlife that can be seen year-round. Many visitors overlook the rich birdlife that makes up part of the regional ecosystem.