Harold Kl Castle Foundation
The Harold K.L. Castle Foundation is a private foundation based in Kailua, Hawaiʻi that invests in public education redesign and enhancement, nearshore ocean resiliency, climate resiliency, and Windward Oʻahu community initiatives.
Source: Website · Mar 2026
Ideal Applicant
A Hawaiʻi-based nonprofit or Hawaiʻi-focused program working in education, nearshore ocean or climate resiliency, or Windward Oʻahu community initiatives with capacity to manage mid-size operating or program grants and partnerships.
Good Fit
- • Primary operations or programs located in Hawaiʻi, especially Windward Oʻahu.
- • Work in public education redesign, youth development, ocean or climate resilience, or community stability.
- • Track record managing grants in the $25K–$250K range or larger partnerships.
- • Willingness to engage as a partner or backbone organization in coordinated initiatives.
- • Clear local community ties and demonstrated collaborative relationships with other Hawaiʻi organizations.
Geography
Giving in the observed year was highly local: about 92% of dollars were directed to organizations in Hawaiʻi, with the remaining funds spread thinly across six other states.
Recipient Variety
The latest year shows broad recipient variety for the foundation's size—80 grants to 59 distinct recipients—indicating many independent organizations were supported rather than a tiny closed circle.
New Applicants
Direct evidence of recipient turnover across years is unavailable, but a public website, application portal, and explicit instructions to contact a named Grants Manager for first-time applicants indicate a clear public entry route and make it plausible that unfamiliar applicants can apply.
Source: Zeffy Agent · Mar 2026
