The lake was originally an arm of San Francisco Bay, fed by several creeks. By 1810, the remaining Ohlone had been forced to Mission San José, and forty-four thousand acres of surrounding land were deeded to Sergeant Luis Maria Peralta as Rancho San Antonio. After the Gold Rush brought Anglo squatters led by Horace Carpentier, the estuary known as San Antonio Slough became Oakland's open sewer. Sixty miles of brick and wood channeling funneled broken-down sewage to the lake bottom, where bottom feeders consumed it. The stench troubled residents on both shores. Yet the wetlands persisted, and migratory birds kept arriving. Oakland's mayor Samuel Merritt, who had the lagoon dammed in the late 1860s to create a stable salt-water lake, proposed protecting the birds from the duck hunters whose gunfire echoed dangerously close to downtown. The state legislature agreed, and in 1870 the Lake Merritt Wildlife Refuge became law - no hunting, fishing by hook and line only.

In 1925, a "necklace of lights" was draped around the lake's 3.4-mile perimeter: 126 lampposts strung with 3,400 pearly bulbs that turned the waterfront into a glowing oval visible from the surrounding hills. When World War II brought blackout conditions in 1941, the necklace went dark. It stayed dark for decades. Not until 1987, after a ten-year campaign by the Lake Merritt Breakfast Club, did the lights return. The 1929 Bellevue-Staten apartments, a fifteen-story blend of Art Deco and Spanish Colonial design completed at 492 Staten Avenue, still anchor the skyline from nearly every vantage point. And the ornate Camron-Stanford House, an Italianate Victorian built in 1876 near the western shore, is the last survivor of the fine homes that once lined the lake - it served as Oakland's public museum from 1910 until 1967 and now operates as its own museum.

The wildlife refuge designation was not ceremonial. Lake Merritt shelters a remarkable year-round population: Canada geese, black-crowned night herons, great and snowy egrets, cormorants, American coots, and western gulls share the shoreline. Brown and American pelicans drift through. From November through March, large flocks of greater and lesser scaup settle on the water alongside canvasbacks, buffleheads, and Barrow's goldeneye. The tufted duck, a rare Eurasian visitor, has been recorded annually. Five artificial Bird Islands, constructed from dredged silt between 1925 and 1956, provide nesting habitat protected by boom barriers from recreational boaters. Beneath the surface, bat rays and gobies navigate the tidal waters, and Chinook salmon have been recorded entering the lake during heavy rains. One resident is found nowhere else on Earth: Transorchestia enigmatica, a tiny crustacean known only from Lake Merritt.

Lake Merritt has spent more than a century under siege. Its natural wetlands were paved over for roads and homes. Storm drains from downtown Oakland flush trash and nitrogen into the water, feeding algae blooms that suffocate fish - an August 2022 bloom triggered a mass die-off. Between one thousand and six thousand pounds of garbage are pulled from the lake every month by volunteers coordinated through the Lake Merritt Institute. Diesel fuel has spilled into the water at least twice. In April 2022, a large encampment fire sent oil cans and debris into the lake. And yet, Oakland keeps fighting for it. Measure DD, a $198 million park bond passed with eighty percent voter approval in 2002, funded the most ambitious restoration in the lake's history: 12th Street was narrowed from twelve lanes to six, tidal flow was partially restored through a 750-foot channel inaugurated in 2013, and the 1913 pergola at the north end was lovingly renovated.

On May 23, 1963, the lake was designated a National Historic Landmark under the name Lake Merritt Wild Duck Refuge. But the real landmark is not the official status. It is the way the lake reflects Oakland itself - diverse, resilient, battered, and stubbornly beautiful. During pride celebrations, the necklace of lights swaps its white bulbs for rainbow colors. Tango dancers gather at the restored gazebo near Children's Fairyland for outdoor milongas. Joggers circle the perimeter on paths that follow the same route where, in 1891, dredged silt was piled to create what became Lakeshore Avenue. The lake that started as a sewer, became a sanctuary, and nearly choked on its own pollution is still here - gnarled New Zealand tea trees leaning over the water's edge, herons standing motionless on the Bird Islands, the necklace glowing after dark.