Telegraph Hill [has been] a visual landmark to sailors entering the Bay since its European discovery by Capt. Juan Manuel de Ayala in the San Carlos on August 5, 1775.

...Telegraph Hill is famous as "the hill that's been around the world" as great portions of it were blasted out for ballast in sailing ships, "ultimately to be used to pave the streets of various exotic places".... The rock was used not only for ballast, but also to build Gold Rush era warehouses (in a combination of brick and stone known as rubble), to fill the Bay for flatlands east of the Hill, and to build the seawall which stabilized San Francisco's waterfront. The last quarrying occurred as late as 1914.

The Historic District is a unique expression of the pattern of development which took place on the east slope of Telegraph Hill from 1850 to 1939.... The difficulty of access on hillside and cliffs, and the proximity to the City's most active waterfront area first produced a community of waterfront workers housed in "cloth lined" shacks and modest vernacular Gothic Revival houses. Intact groupings of these buildings remain within the District, and comprise the City's largest concentration of pre-1870 structures.

[During] the nineteenth and early twentieth centuries, Telegraph Hill remained isolated, bypassed by cablecar or streetcar lines.... Due to the cliffside location, steps, wooden walkways and a hidden network of footpaths developed throughout the area.

Street paving of Montgomery and Alta in 1931 and Union and Calhoun in 1939–1940 improved general accessibility, and heralded new development in the area. Low property values facilitated real estate development. Owners retained an array of architects who produced a collection of noteworthy and (then) innovative designs. Among these are Richard Neutra's International Style Kahn House at 66–70 Calhoun Terrace (1939), and Irvine Goldstine's Art Moderne Malloch Apartment Building at 1360 Montgomery Street (1936). This change in style, scale and pattern of development punctuates the district's period of significance.

The steep cliffs, a decisive factor in determining the historic development pattern of the area, are a highly significant aesthetically important component defining the setting of the District. The abrupt changes in grade produce dramatic and unique vistas at points throughout the District. Unimproved street rights-of-way are valuable open spaces ranging in character from the well-tended, renowned Grace Marchant and Valetta's Gardens on Filbert and Greenwich Streets, to the rock-face cliffs of Green and Calhoun Streets.