In California it mostly comes from the States general fund. Income tax and sales tax. Most of the local property tax also goes to the state to be sent back to the schools on a per student basis, but this is about 25% of the funding. See here [1] for a good explanation of all the crazy details of California school funding and its history.
Prop 13 limited prop tax to 1% of the assessed value (actual property tax also includes many parcel taxes). About 100 school districts out of about a thousand in California have such high property values and/or low number of students that the 1% tax is enough to fund the schools at a higher per student rate than the standard for California. These rich areas are called "basic aid" districts and don't give their prop tax to the state, keeping it local and funding schools at a higher level.
