Harold KL Castle Foundation
The Harold K.L. Castle Foundation is a private foundation based in Kailua, Hawaii. Founded in 1962, it works to build resources for Hawaii’s future through grantmaking, convening, and sharing new ideas and approaches.
Key facts about Harold KL Castle Foundation
In short: Harold KL Castle Foundation gave $6.9M across 106 grants in 2024 (avg $65K), mostly in Hawaii. 36% of 2024 grantees were new. Source: 2024 IRS Form 990-PF.
- EIN
- 99-6005445
- Latest 990 filing
- Form 990-PF, 2024
- Annual giving (2024)
- $6,886,001
- Grants made (2024)
- 106
- Average grant
- $64,962
- Median grant
- $25,000
- New grantees (estimate)
- 36% first-time grantees (30 of 83, 2024)
- Total assets
- $171,295,453
- Primary geography
- Hawaii (83% of itemized 2024 grant dollars)
- How to apply
- Applicants can submit an online inquiry at any time; first-time applicants are asked to discuss their application with Elizabeth Murph first. Full details ↓
- Deadline
- Online inquiries and applications are reviewed on a rolling basis.
Data from IRS Form 990-PF, 2024; updated September 2026. New grantees are estimated by matching recipient names across years (methodology). Application details from Grantable's research on the foundation's public materials; confirm on its website before applying.
Financial Overview
From 2024 IRS Form 990-PF · View filing
Total Assets
$171.3M
-1.3% YoY
Annual Giving
$6.9M
-8.0% YoY
Grant Count
106
-4.5% YoY
Avg Grant Size
$65K
-3.7% YoY
Under IRS private-foundation payout rules, Harold KL Castle Foundation reported a distributable amount of $9.5M for 2024 — the minimum it must pay out in qualifying distributions.
Is Harold KL Castle Foundation open to new grantees?
36%
first-time grantees, 2024
In 2024, 30 of 83 grantees (36%) were first-time recipients. First grants averaged $40K; repeat grants $107K. How we count
Medians: $25K first-time, $40K repeat.
- 48% of 2024 grantees were also funded in 2023. Method
- Giving held roughly steady from 2021 to 2024 (−6%). Method
- In 2024 it paid out 92% of its IRS minimum distribution (the 5% rule). Foundations have until the end of the next year to meet it. Method
Estimate from itemized grant lists in IRS Form 990-PF filings (2020–2024). Recipient names are matched across years, so a renamed or misspelled grantee can look new; grants to individuals are left out. Methodology.
Mission & Focus Areas
The foundation’s stated mission includes closing achievement gaps in public education, restoring Hawaii’s nearshore ocean areas, building on the strengths of Ko’olau Oahu communities, and strengthening communities’ ability to adapt to climate change. It also supports a limited number of other compelling opportunities to make a significant difference in Hawaii’s future.
Eligible applicants include Hawaii-serving nonprofits recognized as 501(c)(3) organizations and 509(a) public charities, as well as public schools. The foundation primarily funds specific projects rather than ongoing general expenses. Its website identifies public education redesign and enhancement (pre-K–12), nearshore marine resource conservation around the main Hawaiian Islands, climate resiliency, and strengthening Windward Oahu communities as its strategic priorities.
Among its 2024 grantees, Social Finance Inc. describes its mission as building partnerships and investments to measurably improve lives. The University of Hawaii Foundation says it raises philanthropic support and manages investments to benefit the university, Hawaii’s people, and future generations. These are grantees’ stated missions, not the foundation’s.
Grantmaking
In filing year 2024, the foundation reported 106 grants totaling $6,886,001. Grant amounts ranged from $500 to $550,000, with a median of $25,000.
Review Cycle
** Online inquiries and applications are reviewed on a rolling basis.
Open Grants
5 open opportunities from Harold KL Castle Foundation
Ko'olau Pilina Fund Grant
Harold KL Castle Foundation
Amount
US $3,000 - US $15,000
Deadline
Rolling / Open
Nearshore Marine Resource Conservation Grant
Harold KL Castle Foundation
Amount
US $100 - US $4,000,000
Deadline
Rolling / Open
Post-Secondary Transition RFP
Harold KL Castle Foundation
Amount
Varies
Deadline
Rolling / Open
Ready to take the next step with Harold KL Castle Foundation?
Geographic Focus
Where this funder awards grants
The foundation says it funds organizations serving the people of Hawaii. Its 2024 filing shows 83% of grant dollars going to recipients in Hawaii, 14% to California, and 4% to Washington, D.C. (percentages as reported). Its grantseeker guidance says it does not consider organizations based outside Hawaii or projects outside Hawaii that do not benefit Hawaii. The Ko’olau Pilina Fund supports projects tailored to Ko’olau communities on Oahu, from Kahuku to Makapu’u.
Grant Distribution by State
Share of all 106 itemized 2024 grant dollars.
Cities
Giving Over Time
Total grant dollars and number of grants per year
Grant Insights
How this funder distributes its grants
Top Recipients
Top 10 recipients in 2024
Grant Size Distribution
500 grants across all recorded years
Giving History
Grant recipients and amounts by year
| Recipient | Purpose | Amount |
|---|---|---|
| SOCIAL FINANCE INC Boston, CA | PROPOSAL TO SERVE AS HAWAII RENEWABLE LEARNING FUND MANAGER [6086; PC] | $550,000 |
| UNIVERSITY OF HAWAII FOUNDATION Honolulu, HI | SOAR HIGHER - SUPPORT FOR WINDWARD OAHU SCHOOLS TO PARTICIPATE AS A GEAR UP 6-16 MODEL [5173; PC] | $529,240 |
| HAWAII COMMUNITY FOUNDATION (HCF) Honolulu, HI | SUPPORT FOR A SECOND ROUND OF CONTRIBUTIONS TO THE HOLOMUA POOLED FUND WHOSE GOAL IS TO IMPROVE MARINE RESOURCES MANAGEMENT IN HAWAII THROUGH A SUITE OF EFFORTS BUILT ON FOUR PILLARS: PLACE-BASED PLANNING, PONO PRACTICES, MONITORING, AND PROTECTION & RESTORATION [5905; PC] | $500,000 |
| KUAAINA ULU AUAMO (KUA) Kaneohe, HI | TO SUPPORT AND STRENGTHEN THIS CRITICALLY IMPORTANT BACKBONE ORGANIZATION AND ITS THREE COMMUNITY-DRIVEN NETWORKS FOR OCEAN MANAGEMENT IN HAWAII. [5598; PC] | $500,000 |
| HAWAII COMMUNITY FOUNDATION (HCF) Honolulu, HI | PILINA FUND 2.0 [5618; PC] | $400,000 |
| THE NATURE CONSERVANCY OF HAWAII Honolulu, HI | ADVANCING COMMUNITY-BASED MARINE MANAGEMENT TO REACH 30X30 GOALS [5660; PC] | $280,000 |
| UNIVERSITY OF HAWAII FOUNDATION Honolulu, HI | TO EXTEND WINDWARD COMMUNITY COLLEGE'S GROUNDBREAKING HOOLEI SCHOLARSHIP THAT ENSURES ALL PUBLIC SCHOOL GRADUATES IN THE KOOLAU REGION CAN AFFORD TO ATTEND COMMUNITY COLLEGE [6140; PC] | $214,286 |
| HAWAII HOSPITAL EDUCATION AND RESEARCH FOUNDATION (HHERF) Honolulu, HI | TO RETROFIT DOE CLASSROOMS FOR HEALTHCARE PATHWAYS IN PARTNERSHIP WITH HAWAII 3R'S, G70 AND HAWAII PACIFIC HEALTH [6363; PC] | $150,000 |
| UNIVERSITY OF HAWAII FOUNDATION Honolulu, HI | HAWAII P-20 CORE SUPPORT 2022-2025 [5465; PC] | $150,000 |
| WINDWARD SCHOOL DISTRICT Kaneohe, HI | TO INTERNALLY DRIVE WINDWARD DOE SCHOOLS TOWARDS AINA ALOHA MINDSET ACHIEVEMENT THROUGH TEACHER PROFESSIONAL DEVELOPMENT (PD) DAYS AND CLOSER ENGAGEMENT BETWEEN SCHOOLS AND AINA-BASED EDUCATION ORGANIZATIONS. [6371; GOV] | $150,000 |
Financial History
Multi-year comparison from IRS filings
| Filing year | Assets | Revenue | Expenses | Grants reported |
|---|---|---|---|---|
| 2024 | $171,295,453 | $8,283,293 | $10,627,064 | $6,886,001 |
| 2023 | $173,491,448 | $11,327,617 | $10,879,744 | $7,485,951 |
| 2022 | $173,044,264 | $8,125,647 | $11,246,442 | $8,009,541 |
| Metric | 2024 | 2023 | 2022 |
|---|---|---|---|
| Total Assets | $171,295,453 | $173,491,448 | $173,044,264 |
| Revenue | $8,283,293 | $11,327,617 | $8,125,647 |
| Expenses | $10,627,064 | $10,879,744 | $11,246,442 |
| Qualifying Distributions | $8,758,237 | $9,503,881 | $9,746,584 |
| Net Investment Income | $7,046,551 | $10,105,204 | $6,568,148 |
| Distributable Amount | $9,515,391 | $8,920,185 | $9,315,597 |
Data update history
When this profile's IRS filing data changed on Grantable
- IRS filings on file for fiscal years 2020–2024
Leadership & Key People
Leadership team and compensation from IRS filings
The foundation’s 2024 filing lists Henry M. D’Olier as director and chairman; Dr. Claire L. Asam, Dr. Kittredge A. Baldwin, Corbett A.K. Kalama, Dee Jay A. Mailer, James H. McIntosh, Jennifer G. Sabas, T. Aulani Wilhelm, and Eric K. Yeaman as directors; and Carlton K.C. Au as vice president of finance.
Harold KL Castle Foundation is led by Terrence R. George, President & CEO on every filing since 2020; 6 of 15 officers listed in 2024 are compensated.
Officers on the 2024 filing
Terrence R. George
President & CEO
On filings since 2020
40 hrs/week
$372K (2020) → $415K (2024)
Henry M. D'olier
Director & Chairman
On filings since 2020
2 hrs/week
No compensation reported
Claire L. Asam
Director
On filings since 2020
0.5 hrs/week
No compensation reported
Corbett Ak Kalama
Director
On filings since 2020
0.5 hrs/week
No compensation reported
Dee Jay A. Mailer
Director
On filings since 2020
0.5 hrs/week
No compensation reported
Eric K. Yeaman
Director
On filings since 2020
0.5 hrs/week
No compensation reported
James H. McIntosh
Director
On filings since 2020
0.5 hrs/week
No compensation reported
Kittredge A. Baldwin
Director
On filings since 2020
0.5 hrs/week
No compensation reported
Jennifer G. Sabas
Director
On filings since 2023
0.5 hrs/week
No compensation reported
T. Aulani Wilhelm
Director
On filings since 2023
0.5 hrs/week
No compensation reported
Alexander Harris
Vice President of Programs
On filings since 2020
40 hrs/week
$228K (2020) → $222K (2024)
Carlton Kc Au
Vice President of Finance
Vice President, Treasurer & CFO → Vice President of Finance, 2023
On filings since 2020
8 hrs/week
$104K (2020) → $55K (2024)
Susan L. Sumida
Secretary
On filings since 2020
5 hrs/week
$21K (2020) → $28K (2024)
Dennis Eric Co
Vice President of Resiliency
On filings since 2022
40 hrs/week
$203K (2022) → $223K (2024)
Ann S. Matsukado
Treasurer
On filings since 2023
40 hrs/week
$98K (2023) → $189K (2024)
Data from IRS Form 990 filings, 2020–2024. "On filings since" is the earliest filing we hold that lists the person; hours are average hours per week as reported.
Compensation Overview
From 2024 IRS filing
Contact
Application contact: Elizabeth Murph
Mailing address: 1197 Auloa Road, Kailua, HI 96734
Phone: (808) 263-7073
Website: https://castlefoundation.org
Frequently asked questions about Harold KL Castle Foundation
How much does Harold KL Castle Foundation give each year?
Harold KL Castle Foundation gave $6.9M across 106 grants in 2024, according to its 2024 IRS Form 990-PF. In 2023 it gave $7.5M across 111 grants.
What is Harold KL Castle Foundation's typical grant size?
Harold KL Castle Foundation's median grant in 2024 was $25,000, and its average grant was $64,962, across 106 grants on its 2024 IRS Form 990-PF. Organizations receiving their first grant from Harold KL Castle Foundation that year got $40K on average.
Where does Harold KL Castle Foundation give grants?
Harold KL Castle Foundation gives mostly in Hawaii: 83% of the grant dollars itemized on its 2024 IRS Form 990-PF went to recipients there. The next largest state was California (14%). The most frequent recipient cities were Honolulu, HI (54 grants), Kaneohe, HI (11 grants), Kailua, HI (9 grants) and Washington, DC (4 grants).
Does Harold KL Castle Foundation give general operating support?
Occasionally: 2% of Harold KL Castle Foundation's 2024 grants with a stated purpose (2 of 106) were for general or operating support, per its 2024 IRS Form 990-PF.
Who are Harold KL Castle Foundation's largest grantees?
Harold KL Castle Foundation's largest 2024 grantees include University of Hawaii Foundation ($1,115,551 across 11 grants), Hawaii Community Foundation (HCF) ($960,000 across 4 grants) and Social Finance Inc ($550,000), according to its 2024 IRS Form 990-PF. Together they received 38% of its itemized 2024 grant dollars.
How large is Harold KL Castle Foundation?
Harold KL Castle Foundation reported $171.3M in total assets on its 2024 IRS Form 990-PF. It paid out $8.8M in qualifying distributions that year, against a required minimum of $9.5M (roughly 5% of its investment assets).
What does Harold KL Castle Foundation fund?
The foundation’s stated mission includes closing achievement gaps in public education, restoring Hawaii’s nearshore ocean areas, building on the strengths of Ko’olau Oahu communities, and strengthening communities’ ability to adapt to climate change. It also supports a limited number of other compelling opportunities to make a significant difference in Hawaii’s future. Eligible applicants include Hawaii-serving nonprofits recognized as 501(c)(3) organizations and 509(a) public charities, as wel…
How do I apply for a grant from Harold KL Castle Foundation?
Applicants can submit an online inquiry at any time; first-time applicants are asked to discuss their application with Elizabeth Murph first. Eligibility and process details are in the grantmaking section of this profile. See how to apply ↑
What is Harold KL Castle Foundation's EIN?
Harold KL Castle Foundation's EIN (Employer Identification Number) is 99-6005445. IRS Form 990 filing data is available on this page for 2020–2024.
Data last updated September 2026. Sourced from IRS Form 990-PF filings. Research dossier generated September 2026.
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