These places in California and the U.S. donated big to charities. Here’s why

Americans who itemized their tax returns gave about $250 billion, or 3.4 percent of their income, to charity in the 2017 tax year, but charitable giving varied significantly between states, according to new IRS statistics.

Charitable giving correlates strongly with religiosity: The states with the highest rates of giving tend to also have high rates of residents who say religion is very important to them.

Utah had the highest rate of charitable giving in the nation in 2017. A significant portion of its residents belong to the Mormon church, which emphasizes tithing, the practice of giving 10 percent of your income to the church. Several states in the Deep South, where evangelical churches also emphasize tithing, gave relatively large portions of their income to charity. The IRS classifies donations to churches as charity.

In California, households that itemized their tax deductions gave about $35 billion, or 3 percent of their income, to charity.

Santa Clara County residents were the most generous, giving about $5.3 billion, or 4.2 percent of their income, to charity. Santa Clara County is home to multiple Silicon Valley millionaires and billionaires.

Tiny Alpine County in the heart of the Sierra Nevada was the stingiest county. Residents who itemized their tax returns in Alpine County gave about 1.8 percent of their income to charity.

In the Central Valley, Sacramento County residents who itemized gave about 2.6 percent of their income in 2017; Fresno County residents gave about 3.2 percent; Stanislaus County residents gave about 2.9 percent and Merced County residents gave about 2.9 percent.

Notes: This analysis only includes taxpayers who itemize their tax returns. Most tax filers making more than $75,000 a year itemized in 2017, and vice versa. That year, itemized tax returns accounted for about two-thirds of the personal income reported to the IRS.

The U.S. Congress recently passed tax changes that raised the standard deduction and made it less likely people will itemize their taxes, but those changes did not take place until the 2018 tax year. This data covers the 2017 tax year.

All data for this analysis comes from IRS county-level data, including state totals. The state totals in this analysis may be slightly off “because of disclosure protection procedures or the exclusion of returns that did not match based on the ZIP code,” according to the IRS. More details and caveats can be found here.