ROSEVILLE, Calif.—Residential and commercial real-estate owners aren't the only ones losing their properties to foreclosure. The past few years have seen a rapid acceleration in the number of churches losing their sanctuaries because they can't pay the mortgage.

Just as homeowners borrowed too much or built too big during boom times, many churches did the same and now are struggling as their congregations shrink and collections fall owing to rising unemployment and a weak economy.

Since 2008, nearly 200 religious facilities have been foreclosed on by banks, up from eight during the previous two years and virtually none in the decade before that, according to real-estate services firm CoStar Group, Inc. Analysts and bankers say hundreds of additional churches face financial struggles so severe they could face foreclosure or bankruptcy in the near future.

"Churches are the next wave in this economic crisis," says Rev. Jesse L. Jackson Sr., president and founder of the Rainbow PUSH Coalition, a non-profit civil-rights group, who works with pastors around the country to help churches negotiate better terms with their bankers.

Religious denominations of all kinds have suffered in recent years as donations have declined, with many Catholic parishes closing and synagogues merging their congregations. But the property-financing problems have been concentrated among independent churches, which while seeking to expand lack a governing body to serve as a backstop to financial hardship.