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Strengthening Windward O‘ahu Communities Grant

Harold K. L. Castle Foundation

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Grant amount: US $5,000 - US $2,000,000

Anticipated deadline: The deadline for this grant has passed

Applicant type: Government Entity Nonprofit Indigenous Group

Funding uses: Education / Outreach, Applied Project / Program

Location of project: Honolulu County, Hawaii

Location of residency: Hawaii

About this funder:

View past grantees & full 990 summary


NOTE: The Online Inquiry portal has been disabled. If you’ve already spoken to the program officer and they think your project is a fit, we are allowing grantees to submit their inquiry. Please check in with the appropriate program officer to ensure that your request aligns with our mission.

Strengthening Windward O‘ahu Communities

Windward O‘ahu Strategy: Building social, human, and natural capital with a particular emphasis towards nurturing future community leaders.

The Harold K.L. Castle Foundation builds on the strengths of vibrant Windward O‘ahu communities through investments that support the region’s rich cultural legacy, its youth and families, and its natural resources.

Like many Hawai‘i-based organizations, the Foundation is rooted in a strong sense of community and place. Prior to creating a family foundation in 1962, Harold K.L. Castle gave generously of his time, energy, and financial resources to the Windward O‘ahu community in which he lived and worked. With an eye toward the future and a vision of building civic and cultural resources, Mr. Castle in his lifetime made substantial gifts of land for Windward churches and schools, and for institutions such as Castle Medical Center and the Windward YMCA. Over its 44-year history, the Foundation has maintained a deep connection to its roots in Windward O‘ahu and a commitment to contributing to the vitality of communities from Kahuku to Waimanalo.

Our Strategy

The Harold K.L. Castle Foundation helps communities build assets in Windward O‘ahu by strengthening and supporting the region’s rich cultural legacy, its youth and families, and its natural resources. Investing in the unique history, traditions, people, and environment of Windward O‘ahu has important implications for the state as a whole, and is an important piece of the foundation’s commitment to “Building Resources for Hawai‘i’s Future.”

Our average grant size is approximately $110,000, but grants range from $100 to $4 million.

You can learn more about this opportunity by visiting the funder's website.


  • Eligible applicants:
    • Nonprofit organizations serving Hawai‘i with Internal Revenue Code Sections 501(c)(3) and 509(a) public charity status
    • Public schools


  • The Harold K.L. Castle Foundation generally prefers not to be the only funder of a given project. 


  • Proposals are not considered for:
    • Individuals or businesses
    • Ongoing operating expenses (unless it is a new project or organization needing start-up funding)
    • Vehicles
    • Computers
    • Endowments
    • Annual fund drives
    • Sponsorships, special events, dinners, galas
    • Organizations based outside of Hawai‘i
    • Projects taking place outside Hawai‘i that do not benefit Hawai‘i