Methodology
CaliSplit assigns each of California's 58 counties to one of two hypothetical states and compares them using authoritative, pre-processed data. Sources and methods are below. This is an educational thought experiment, not affiliated with any campaign or government.
Data sources & vintages
| Group | Fields | Source | Year |
|---|---|---|---|
| Demographics | population, median age, race/ethnicity, % bachelor's+ | U.S. Census Bureau, American Community Survey 5-year | 2024 |
| Demographics | urban / rural population | U.S. Census Bureau, 2020 Census (DHC, table P2) | 2020 |
| Economy | median household income, poverty, labor force / unemployment | U.S. Census Bureau, American Community Survey 5-year | 2024 |
| Economy | county GDP (all-industry total) | U.S. Bureau of Economic Analysis, CAGDP2 | 2024 |
| Economy | state GDP (national comparison) | U.S. Bureau of Economic Analysis, SAGDP2 | 2024 |
| Government & fiscal | federal funding received | USAspending.gov (spending by recipient county) | FY2025 |
| Government & fiscal | state income tax generated | California Franchise Tax Board, B-6 Comparison By County (self-assessed PIT liability by county of residence, via data.ca.gov) | tax year 2022 |
| Government & fiscal | U.S. House seats / electoral votes | U.S. Census Bureau, 2020 Census apportionment | 2020 |
| Land & misc | land area | U.S. Census Bureau, cartographic boundary files (ALAND) | 2023 |
| Land & misc | largest cities | ACS place populations + curated city→county mapping | 2024 |
| Land & misc | national parks, coastline (coastal flag) | Curated (National Park Service designations; Pacific-fronting counties) | 2024 |
How the numbers are computed
- Additive: Population, land area, GDP, federal funding, counts: summed.
- Derived: GDP per capita, density, unemployment %, poverty %, % bachelor's+: computed from summed components (exact).
- Weighted: Median household income: computed by summing each county's household income-bracket counts (Census B19001) and interpolating the median of the combined distribution (accurate, not a median-of-medians). Median age: population-weighted average of county medians (approximation).
- Apportionment: California's 52 U.S. House seats are divided between the two new states proportional to population (min 1 each); EV = seats + 2.
- Ranking baseline: 49 non-California states (as-is) + the two new states = 51.
State income tax (“Who funds Sacramento?”)
- State income tax figures are FTB self-assessed liability by county of residence for tax year 2022 (the most recent county-level year published), not cash collections. PIT is volatile year to year — statewide liability fell from ~$125B (2021) to ~$98B (2022) with the capital-gains downturn.
- The personal income tax supplies over half of California's General Fund and is where the state's redistribution is concentrated: roughly half of PIT comes from filers earning over $1 million. Counties' shares of it differ far more than their shares of population.
- The remaining General Fund taxes cannot be allocated to counties: the state does not publish corporation tax (~21% of the General Fund) by county, and sales tax by county is distorted by the situs rule, which credits online sales to the seller's warehouse county rather than the buyer's.
- The 'what it would mean for residents' figures compare each new state's per-resident income tax to the current statewide average — the funding level today's service mix (schools under Prop 98, Medi-Cal, universities, transportation) is built on. They assume both states keep California's current tax rates and service levels; an actual new state could choose different taxes and services. Federal funding is shown separately and mostly follows people, programs, and facilities rather than state lines.
Preset splits
- AJR 23 “Two-State Solution” (2025): State B is the 36 inland counties enumerated in Assembly Joint Resolution 23 (Gallagher, 2025), the “Two-State Solution” — including Orange County but not Los Angeles or San Diego. State A is the 22-county coastal remainder. Source: the resolution's text at leginfo.legislature.ca.gov.
- State of Jefferson: State B is the cluster of far-northern, mostly rural counties historically associated with the State of Jefferson secession movement; many have passed declarations of support. State A is the rest of California.
- North vs. South California: State B is the ten traditional Southern California counties lying south of the Tehachapi Mountains (the 1956 'Tehachapi line' definition used by past north/south split proposals). State A is the northern remainder.
- Coastal vs. Inland: State B is the fifteen counties that front the Pacific Ocean; State A is the inland remainder. Captures the coastal/urban vs. inland/rural divide.
- 2024 Election: Harris vs. Trump: State B is the 33 California counties Donald Trump won in the 2024 presidential election; State A is the 25 counties Kamala Harris won. Source: California Secretary of State, Statement of Vote (President), 2024 General Election.
Metrics not included
- state sales & corporation tax by county: Corporation tax is not published by county; county sales-tax figures are distorted by the situs (warehouse) rule. See the state income tax notes above.
- agricultural output: USDA NASS QuickStats requires a separate API key; deferred for v1.
- top industries: Requires per-county GDP-by-industry breakdown (heavy BEA fetch); deferred for v1.
Reuse, citation & press
CaliSplit's maps, share images, screenshots, and computed statistics are free to reproduce for any purpose — news coverage, classrooms, research, social media — with attribution to calisplit.com (a link where possible). The underlying data comes from the public sources listed above. No permission request is needed.
This grant covers CaliSplit's own maps, images, and statistics. News headlines and editorial summaries elsewhere on the site describe other outlets' reporting and remain theirs; please cite the linked originals.
No county values required estimation or gap-filling — all 58 counties have complete source data for every included metric.