San Francisco is famously full of hills, but one stands apart. Just to the north of the Castro District, one lone crag pokes out, its sides sheared and exposed — Corona Heights. If you’re intrepid, it may remind you of the southeastern corner of Telegraph Hill, and of Billy Goat Hill at the southern end of Noe Valley. This is not a coincidence.

Corona Heights’ rugged appearance is the product of the Gray brothers, George and Harry, who quarried the facade for rock used in construction, street paving, and Bay fill. The remains of their brick factory can still be seen on the southern slope. The Gray Brothers’ product were important in the construction of San Francisco. However, they were infamously unscrupulous.

Telegraph Hill was their first quarry. They dynamited the hillside with little regard for the neighbors other than scheduling their explosions so people could hunker down. In January 1895, their explosions caused a landslide that destroyed a duplex and knocked another home off its foundation.

In 1899, they began quarrying Corona Heights and set up their brick factory there. Many of the bricks were used in Cable Car track beds, but were later determined to be of inferior quality and had to be replaced. The factory was badly damaged in the 1906 quake, but was rebuilt. The company came to an end when an employee, disgruntled at not receiving his pay, shot and killed George Gray at the Billy Goat Hill quarry. So unpopular were the Grays that the employee was fond not guilty by reason of temporary insanity and released.

Today, the top is the Corona Heights Park, with hiking trails and sweeping 360º views. The nearby Randall Museum is a free museum delighting children of all ages with exhibits of art and nature. The streets that were carved out of the hillside to create passages for quarried rock now are lined with some of the city’s most desirable real estate. Because of its hilly terrain, the neighborhood has many charming public right-of-way stairways.

Corona Heights has no commercial center, having only a small number of corner stores within its boundaries, but is easily accessible to the Castro, Duboce Triangle, Haight Street, and the Divisadero Corridor.