California Secretary of State records show dozens of Idaho residents sent $10,000, $5,000 and $1,000 donations to ProtectMarriage.com, an online-based campaign in support of the ban.
Voters in California narrowly passed Proposition 8 in the Nov. 4 election. The ballot proposition amends the California constitution to define marriage as between a man and a woman.
The ProtectMarriage.com campaign collected a total of about $40 million for its Yes on Proposition 8 campaign, according to a statement posted on its Web site.
The Idaho donations were collected in a span of less than two weeks, beginning on Oct. 27 and ending on Election Day, and a bulk of the money came from the eastern region of the state.
The wife of Frank VanderSloot, president and CEO the Melaleuca Inc. healthcare products company, donated $100,000 and Idaho Falls businessman Kreg Davis donated $15,000 to the ProtectMarriage.com campaign.
Davis said his uncle is gay and lives in California with a partner.
"I want them to be treated with respect and dignity," Davis told the Post Register. "I want them to have equal rights and equal pay. At the same time, I believe children should be raised by a mom and a dad."
Brigham Young University-Idaho President Kim Clark put $5,000 toward efforts to pass the ban. The university is owned by The Church of Jesus Christ of Latter-day Saints, which played a vigorous role in the campaign to pass Proposition 8.
At the behest of church leaders, thousands of Mormons worked as grassroots volunteers and gave tens of millions of dollars to the campaign. Like many other religious groups, Mormons consider traditional marriage a sacred institution ordained by God.
By changing the state constitution to limit marriage to a man and a woman, Proposition 8 overturns a California Supreme Court decision in June that overturned a 2000 ban and legalized same-sex marriage.
Since then, an estimated 18,000 gay and lesbian couples have been married.
Two years ago, more than 60 percent of Idaho voters passed a similar state constitutional ban on gay marriage.
Southeastern Idaho resident Ellen Rosenau, who lives part of the year in Oakland, Calif., gave $150 to a campaign in opposition to the gay marriage ban.
The 73-year-old retiree said her gay friends are "very surprised and very hurt" the proposition passed.