On the Windward side of Oahu, the Harold K.L. Castle Foundation is pretty much a household name.

Community organizations and schools in the area, both big and small, have received grants from the largest private foundation based in Hawaii at one time or another through the decades.

This year marks the foundation’s 50th year of giving.

Since its inception in 1962, the foundation has awarded more than $176 million in grants, with more than $55 million going toward organizations serving Windward Oahu.

"I’m pretty amazed at the range of good work that’s been happening in Hawaii," said foundation Vice President and Chief Operating Officer Terrence R. George. "Yet I think there’s a lot more to be accomplished."

The foundation’s mission, quite simply, is to make Hawaii a better place, with three target goals: close the achievement and college completion gap in public education, restore nearshore marine ecosystems and strengthen Windward Oahu communities (from Wai­ma­nalo to Kahuku).

While the foundation used to give grants to a broad gamut of causes, the board of directors identified these three goals as critical for the future of Hawaii about 10 years ago.

"We’re in the business of making a difference by trying to help the best, brightest and most dedicated leaders of the state, from grass roots to the grass tops, to create permanent solutions to seemingly intractable problems," said George.

The foundation has about $6 million to $7 million to work with a year, and looks for creative ways to leverage its grants.

Some examples of the foundation’s dollars at work include a $114,000 grant to the U.S. Educational Delivery Institute for public education reform last year, when the state was in jeopardy of losing its Race to the Top grant.

The foundation also offered a grant of $500,000 to The Nature Conservancy of Hawaii in 2011 for its "supersucker project," which uses an underwater vacuum to help clear invasive algae from the reef.

Over the last few years, the foundation also helped a nonprofit called Kako‘o ‘Oiwi get off the ground with its long-term project of restoring 405 acres of long-abandoned wetlands in Heeia with grants of $50,000 and $150,000 in 2010 and 2011.

The group continues to remove invasive mangrove and hau trees from the wetlands and to rebuild the taro farms that once thrived there. The project invites the community to participate, serving as an educational and cultural resource while cultivating taro.

"In each of these cases, we’re interested in the long-term impact," said George.

The foundation was established in 1962 by the late Castle & Cooke partner Harold K.L. Castle and his wife, Alice Hede­mann Castle, who wanted to help build a vibrant community on the Windward side.

Upon his death in 1967, Castle bequeathed a sizable portion of his real estate assets to the foundation, which are the base from which its grants are made.

The potential sale of the majority of Kailua commercial real estate holdings will not affect the foundation, George said.

"It’s not going to affect us at all except to potentially make us financially stronger," he said. "We’ll be in the same building, with the same staff and mission."

In 1963, its first year of giving, the foundation had $2,856.16 to distribute. The money was divided and given to six organizations, including the Boy Scouts, Girl Scouts, YMCA and Castle hospital.

Today Castle’s list of grant recipients includes the Bishop Museum, Hawaii Community Foundation, Hawaii Pacific University, the Polynesian Voyaging Society and the University of Hawaii Foundation.

Recently the Castle Foundation’s board of directors approved a $43,000 grant to the Wai­ma­nalo Health Center to bring dentists to students at Blanche Pope Elementary School.

The foundation also offered $150,000 to Malama Mau­na­lua for the restoration of Mau­na­lua Bay and $41,244 to the UH Foundation to improve college completion.

Grants can be as small as $800 to help fund World Wetlands Day in Kailua to $2 million to help Castle Medical Center renovate its facilities.

The foundation cultivates the next generation of leaders by encouraging Windward youth to apply for and earn up to $5,000 for their club or group activities by doing something positive for the community.

"We’re not about cynicism," said George. "We’re about possibilities. We fund dreamers who have their heads in the clouds and feet on the ground."