Updated July 2026
Child Support in Northern California, California
A plain-language guide to child support across Northern California, from California's statewide guideline formula to the forms you file at your county's Superior Court, the local child support agency, and how to estimate your number and prepare your paperwork without hiring an attorney.
This page covers child support in 13 of California's smaller, largely rural northern counties: Mendocino and Del Norte on the coast, Tehama, Glenn, Colusa, Sutter, and Yuba in the Sacramento Valley, Siskiyou, Lassen, Modoc, Trinity, and Plumas in the mountains and high desert, and Lake around Clear Lake. Each keeps its own Superior Court and Local Child Support Agency, and each applies the exact same statewide rules as every other California county. They are grouped on one page because they share the practical realities of a small county, not because the formula changes.
California sets child support with a single statewide guideline formula (Family Code section 4055), based mainly on both parents' net disposable incomes and the timeshare, the percentage of time the child spends with each parent. The guideline amount is presumed correct in every county on this page, exactly as it is statewide. You can reach a support order two ways: by filing a Request for Order (Form FL-300) with an Income and Expense Declaration (Form FL-150) in a divorce, parentage, or custody case, or by asking the county's Local Child Support Agency, part of the California Department of Child Support Services, to open and enforce a case.
Because the result turns on the income and timeshare figures you report, estimating early is worth doing. Try our free California child support calculator before you file. What differs locally in a small county is mostly administrative: many of these counties route filings through a single courthouse, and both the court's self-help center and the Local Child Support Agency office can have more limited hours than a metro county, so confirm current locations using the official California Courts court finder before you file or travel.
Child support in California generally continues until the child turns 18, or 19 if the child is still a full-time high school student living at home and not self-supporting, and either parent can ask the court to modify support when income or timeshare changes meaningfully. This applies the same way in every county listed here.
Estimate your Northern California child support
California uses one statewide guideline formula, so you can get an estimate for a case anywhere in Northern California with our free calculator before you file.
Open the California guideline child support calculatorChild support agencies and courts by county in Northern California
Mendocino County
Mendocino County serves families in Ukiah, the county seat, Fort Bragg, and Willits through the Superior Court of California, County of Mendocino and its Local Child Support Agency. Confirm the correct courthouse and agency office using the official California Courts court finder and the California Department of Child Support Services before filing.
Lake County
Lake County's family courts and Local Child Support Agency handle support matters for Clearlake and Lakeport, the county seat, through the Superior Court of California, County of Lake, generally at a single office.
Tehama County
Tehama County serves families in Red Bluff, the county seat, and Corning through the Superior Court of California, County of Tehama and its Local Child Support Agency.
Siskiyou County
Siskiyou County's family courts and local child support agency handle support cases for Yreka, the county seat, Mount Shasta, and Weed, through the Superior Court of California, County of Siskiyou.
Lassen County
Lassen County's family courts and Local Child Support Agency serve families in and around Susanville, the county seat, through the Superior Court of California, County of Lassen.
Glenn County
Glenn County serves families in Willows, the county seat, and Orland through the Superior Court of California, County of Glenn and its Local Child Support Agency.
Del Norte County
Del Norte County's family courts and local child support agency handle support cases for Crescent City, the county seat and only incorporated city, through the Superior Court of California, County of Del Norte.
Colusa County
Colusa County serves families in Colusa, the county seat, and Williams through the Superior Court of California, County of Colusa and its Local Child Support Agency.
Plumas County
Plumas County's family courts and Local Child Support Agency serve families in Portola and Quincy, the county seat, through the Superior Court of California, County of Plumas.
Trinity County
Trinity County serves families in and around Weaverville, the county seat and only incorporated city, through the Superior Court of California, County of Trinity and its Local Child Support Agency.
Modoc County
Modoc County's family courts and local child support agency handle support cases for Alturas, the county seat and only incorporated city, through the Superior Court of California, County of Modoc.
Sutter County
Sutter County serves families in Yuba City, the county seat, and Live Oak through the Superior Court of California, County of Sutter and its Local Child Support Agency.
Yuba County
Yuba County serves families in Marysville, the county seat, and Wheatland through the Superior Court of California, County of Yuba and its Local Child Support Agency.
Find your county's Superior Court (official California Courts finder)
How child support is calculated in California
California sets child support with a statewide uniform guideline (Family Code section 4055) that applies the same way in every county in Northern California as everywhere else. The formula is based mainly on two things:
- Both parents' net disposable incomes.
- The percentage of time the child spends with each parent (the timeshare).
The guideline amount is presumed to be correct, and courts use a calculator to run the numbers. Because the result depends on accurate income, the Income and Expense Declaration (Form FL-150) you file is what drives your number.
Guides and tools for your child support case
Northern California Child Support FAQs
How is child support calculated in these Northern California counties?
Every county on this page uses California's statewide guideline formula (Family Code section 4055), based mainly on both parents' net disposable incomes and the percentage of time the child spends with each parent. The guideline amount is presumed correct, and you can estimate your number with our free California guideline child support calculator before you file.
Can the Local Child Support Agency help with my case in a county like Tehama or Glenn?
Yes. Each of these counties has a Local Child Support Agency, part of the California Department of Child Support Services, that can establish parentage if needed, set a guideline order, and collect and enforce payments, often at no cost to the parents. You can also file on your own with a Request for Order (Form FL-300).
How long does child support last in these counties?
Under California law, which applies the same way in every county on this page, child support generally continues until the child turns 18, or 19 if the child is still a full-time high school student living at home and not self-supporting. Either parent can request a modification when income or timeshare changes meaningfully.
Can I handle a child support filing without a lawyer?
Yes. California allows self-represented parents, and each of these counties offers self-help resources for people handling their own support paperwork. A document preparation service like Virdix can help you complete the required Judicial Council forms accurately, though it does not give legal advice or represent you in court.
This page is general information about California child support procedure in Northern California, not legal advice for your situation. The calculator provides an estimate only, and the court determines the actual guideline amount. Court locations, agency offices, and filing details change; always confirm current details with your county's Superior Court, its Local Child Support Agency, or the official California Courts self-help resources. Virdix is a document preparation service, not a law firm, and is not a substitute for an attorney.