San Francisco County is unique—it consists entirely of the City and County of San Francisco, California’s cultural and financial heart. Established in 1850, it occupies roughly 47 square miles on a peninsula between the Pacific Ocean and San Francisco Bay. The city’s topography of steep hills, narrow valleys, and waterfront views defines both its beauty and its building challenges. Neighborhoods such as Nob Hill, Pacific Heights, Mission District, North Beach, and the Sunset each carry distinct personalities and architectural styles—from iconic Victorian “Painted Ladies” to sleek high-rises and modern condos. Housing density is extremely high; single-family homes are scarce compared with apartments or condos. Median sale prices in 2025 average around US $1.4 – 1.6 million, while luxury properties can exceed US $3 million. Building new is prohibitively expensive due to land scarcity and permits, often US $700 – 900 per sq ft. San Francisco is purely urban, dense, and walkable; nearly every neighborhood has proximity to major employment, restaurants, and transit. It sits immediately north of Silicon Valley and across the Bay from Oakland and Berkeley. Despite its small footprint, the county remains one of the world’s most recognized metropolitan destinations.