Answer: Opened to the public in 1855, as an amusement park, what was San Francisco’s most popular resort until it closed in 1892?

Answer: Woodward’s Gardens

Woodward’s Gardens occupied the block bounded by Mission, Duboce, Valencia, and 14th Streets with the main entrance on Mission Street. R. B. Woodward opened his gardens to the public in 1866, as an amusement park catering to all tastes. It was San Francisco’s most popular resort until it closed in 1892.

State Registered Landmark No. 454
Tablet placed by California Centennials Commission with he cooperation of the Society of California Pioneers 
Dedicated December 15, 1949.

source: www.noehill.com