| Statistic | Altadena | California | National |
| Population | 44,242 | 40,994,941 | 336,919,644 |
| Population density (sq mi) | 5,077 | 263 | 91 |
| Median age | 45.4 | 36.0 | 37.7 |
| Male/Female ratio | 0.9:1 | 1.0:1 | 1.0:1 |
| Married (15yrs & older) | 57% | 52% | 55% |
| Families w/ Kids under 18 | 34% | 46% | 43% |
| Speak English | 65% | 56% | 79% |
| Speak Spanish | 23% | 29% | 13% |

The demographics of Altadena offer invaluable insights into the composition, dynamics and needs of both urban and rural areas, empowering planners, developers and policymakers to foster prosperity, equity, and well-being for all residents. With a population of 44,242, Altadena exhibits a population density of 5,077 people per square mile, contrasting with the national average of 91. The median age stands at 45.4, with 57% of individuals aged 15 or older being married and 34% having children under 18. In terms of income equality in Altadena, 11% of households report a median income below $25,000, while 40% report an income exceeding $150,000, showcasing a diverse economic landscape.
Understanding the Altadena racial demographics and ethnic composition is paramount for addressing systemic inequities, advancing social justice and inclusion and fortifying communities. In Altadena, the racial breakdown indicates 53.2% White, 19.7% Black or African American, 5.2% Asian, 0.6% American Indian and 0.1% Native Hawaiian, with 29.5% of the population identifying as Hispanic or Latino. Notably, 64.7% of households reported speaking English only, while 22.6% reported speaking Spanish only. Additionally, 23% of residents were categorized as foreign-born.
High population density areas are renowned for their extensive array of amenities and services, easily accessible to residents within walking distance or a short commute. From healthcare facilities and educational institutions to cultural venues, dining establishments, retail shops and public transportation options, these communities offer convenience and enrichment to their inhabitants. The Altadena population density is 5,077 people per square mile, well above the national average of 91, making it one of the most densely populated cities in the nation.
Social Cohesion: The analysis and understanding of demographics are essential for promoting social cohesion and fostering appreciation among diverse communities. By embracing and acknowledging differences in Altadena demographics, societies can promote inclusivity, diversity and social harmony while addressing social inequalities and advocating for equal opportunities. Racial demographics can reflect the diversity within a population and are instrumental in fostering inclusive and welcoming communities. Embracing ethnic diversity strengthens social connections, promotes cultural understanding and enriches society by celebrating the contributions of individuals from diverse racial and ethnic backgrounds.
Healthcare Planning: An analysis of Altadena demographics can inform healthcare planning and delivery by identifying population health needs, disparities and risk factors. Understanding demographic trends allows healthcare providers and policymakers to allocate resources effectively, develop prevention and intervention programs and address health inequities within communities. Leveraging demographic data, healthcare providers, and policymakers strive to achieve equitable, accessible, and high-quality healthcare for all individuals and communities. This proactive healthcare planning approach ensures targeted interventions, efficient resource allocation and customized healthcare services to meet the diverse needs of populations.
Understanding Populations: Reporting and analyzing the demographic data in Altadena can allow us to gain insights into the characteristics and composition of populations, including age, gender, race, ethnicity, income, education and other socio-economic factors. This understanding is essential for addressing the diverse needs, preferences and challenges of different demographic groups within communities. Demographics can play a crucial role in understanding populations, informing decision-making processes and promoting equity, inclusion, and well-being for all individuals and communities. Altadena population data serves as a foundation for addressing social, economic, and environmental challenges and promoting the well-being and resilience of societies.

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| Race | Altadena | California | National |
| White | 53.18% | 61.26% | 73.35% |
| Black | 19.67% | 5.85% | 12.63% |
| Asian | 5.16% | 13.85% | 5.22% |
| American Indian | 0.64% | 0.74% | 0.82% |
| Native Hawaiian | 0.10% | 0.39% | 0.18% |
| Mixed race | 6.94% | 4.62% | 3.06% |
| Other race | 14.31% | 13.28% | 4.75% |