Californians create, organize, and nurture one of the world's richest arts and cultural ecologies. Across diverse landscapes, they preserve traditions and unveil cutting-edge new artwork. As artists, cultural leaders, community-builders, and arts lovers, they build organizations that nurse creativity from conception through production, presentation, and participation. California's arts and cultural ecology encompasses complex ties among people, organizations, and places. An ecological approach underscores the prominence and contributions of these arts ecology components and how they can be strengthened, especially in times of economic austerity. California's arts and cultural nonprofits play an initiating and pivotal role in this ecology. They are important shapers of the state's internationally renowned cultural industries. They preserve, commission, and present a cornucopia of music, performance, heritage, and visual arts to people in all of the state's regions, across age groups and ethnicities at all levels of income and wealth. Our study documents the budget size, disciplinary focus, and intrinsic and economic impacts of nearly 11,000 California arts and cultural nonprofits, mapping them onto cities and regions. We use new data from the California Cultural Data Project, The National Center for Charitable Statistics, the American Community Survey, the Survey of Public Participation in the Arts, and Impact Analysis for Planning. To explore causal connections, we correlate elements of this mosaic with community characteristics. We detail how people work for the sector, volunteer, and make financial contributions. We show the overall impact of people and organizations on California's economy in terms of jobs, income, output, and state and local tax revenue. With interview data, we offer qualitative insights into governance, interorganizational relationships, and special challenges for small nonprofits. California's nonprofit arts and cultural organizations California hosts more nonprofit arts and cultural organizations than do most of the world's nations. Their ranks include multipurpose cultural centers, science and visual arts museums, symphony orchestras and folk ensembles, artist service organizations, ethnic arts groups, literary societies, dance companies, professional associations, and many more. Some have no formal budgets, do little fundraising, and operate chiefly on energetic contributions of volunteers. Others manage sizable budgets with extensive staff, run large productions and venues, and rely less on volunteers. California's nearly 11,000 arts and cultural nonprofits operate across the state's regions. Smaller organizations vastly outnumber large ones, with 85% of organizational budgets falling under $250,000 and 48% under $25,000. Yet California's nonprofits have a much larger footprint than formal budgets convey, because at all budget sizes, they engage the services of substantial numbers of volunteers and receive in-kind contributions of time and materials uncommon in public and for-profit sectors. Reflecting California's ethnic diversity and its immigrant character, 22% of California's arts and cultural nonprofits focus on ethnic, folk arts, and multidisciplinary work. Another fifth focus on humanities, legacy, and other museums. Visual arts organizations, including art museums, comprise 5% of California nonprofits, but 10% of those with budgets over $10 million.