Which State Has the Largest Population? California Leads the U.S. in 2025

The question of which U.S. state has the largest population has a clear answer in 2025: California. With an estimated 39.34 million residents as of July 1, 2025, California remains by far the most populous state in the nation, a position it has held for decades. Its population is larger than the combined total of the 21 least populous states, and it accounts for roughly one in every nine Americans.

Key Numbers

• Largest state population (2025): California — 39.34 million
• Share of U.S. population: about 11.5%
• U.S. total population (July 1, 2026): 342,620,143
• Least populous state (2025): Wyoming — 588,750
• California vs. Wyoming: California has about 67 times more residents
• Nine most populous states: contain slightly more than half of the U.S. population
• 25 least populous states: contain less than one-sixth of the total
• California vs. 21 smallest states: California alone has more people than those 21 states combined

Explanation

State population rankings are based on resident population estimates produced by the U.S. Census Bureau. These estimates count all people living in a state, including citizens, non-citizens, and authorized or unauthorized immigrants, as long as they reside there. The most recent complete vintage is Vintage 2025, covering April 1, 2020, to July 1, 2025.

California has topped the list since the 1960s, when it surpassed New York. Its large population reflects a combination of historical migration, international immigration, a large natural increase (births minus deaths), and a vast, diverse economy. Although domestic out-migration has slowed growth in recent years, California’s base population is so large that it remains far ahead of second-place Texas.

At the other end, Wyoming has the smallest population, with about 588,750 residents in 2025. The gap between the largest and smallest states illustrates the extreme concentration of the U.S. population: the nine most populous states hold slightly more than half of all Americans, while the 25 least populous states hold less than one-sixth.

Definition

In U.S. census terminology, resident population refers to the number of people whose usual place of residence is in a particular state, regardless of legal status or citizenship. The Census Bureau’s Population Estimates Program updates these figures annually between decennial censuses. The 2025 estimates are the latest full-year state population figures available as of early 2026.

Ranking Table

The table below shows the most recent official population figures for the largest and smallest states, along with the national total. Because the Census Bureau’s state-level estimates are released for July 1 of each year, the 2025 figures are the most current complete state data.

Note: The U.S. total shown is the July 1, 2026, national estimate from the Census Bureau’s Population Clock; state-level estimates are for July 1, 2025.

State Comparison

Comparing California and Wyoming highlights the scale of population concentration. California has roughly 67 times the population of Wyoming. Even more striking, California’s population exceeds the combined total of the 21 least populous states, according to the Census Bureau’s analysis of the 2020 census. The table below summarizes key contrasts.

Largest States

While California is the clear leader, the next most populous states are also concentrated in the South and Northeast. According to the Census Bureau, the nine most populous states contain slightly more than half of the total U.S. population. Although the sources provided do not list every state’s exact 2025 figure, established rankings place Texas, Florida, New York, and Pennsylvania among the top five. California’s lead over Texas is roughly 8 million people, a gap that has narrowed slightly in recent years but remains substantial.

California’s size is not just a function of land area; it is driven by large metropolitan regions such as Los Angeles, the San Francisco Bay Area, and San Diego. These urban centers anchor the state’s economy and attract both domestic and international migrants.

Smallest States

Wyoming has been the least populous state for many years. Its 2025 population of 588,750 is smaller than that of many U.S. cities — in fact, the Census Bureau notes that Wyoming has fewer residents than any of the 31 most populous U.S. cities. Other small states include Vermont, Alaska, North Dakota, South Dakota, and Delaware, but Wyoming remains at the bottom.

The 25 least populous states together contain less than one-sixth of the U.S. population, underscoring how population is distributed unevenly across the country.

Population Change

California’s population growth has slowed in recent years due to domestic out-migration — more people moving from California to other states than moving in. However, international immigration and natural increase (births minus deaths) have kept the state’s total from declining sharply. The Census Bureau’s components of change data for 2020–2025 show that California’s annual population change is now modest compared with faster-growing states in the South and West, such as Texas and Florida.

Wyoming, by contrast, has a small base population and relatively slow growth, though it can experience percentage swings due to energy-sector employment. In absolute terms, even a large percentage increase in Wyoming adds only a few thousand people, while a small percentage change in California can mean hundreds of thousands of residents.

Historical Data

California became the most populous state in the early 1960s, overtaking New York, which had held the top spot for more than a century. The state’s population surged after World War II, driven by defense industries, aerospace, entertainment, and later technology. By the 1970 census, California had more than 19 million residents, and it crossed 30 million by 1990. The 2020 census counted 39.5 million people in California, and the 2025 estimate of 39.34 million reflects a slight decline from the 2020 peak, largely due to domestic out-migration during the pandemic years.

Wyoming’s population has remained below 600,000 for most of its history, reflecting its rural character and limited economic base outside energy and tourism.

Why It Matters

State population size affects congressional representation, Electoral College votes, and the distribution of federal funds. California’s large population gives it 52 seats in the U.S. House of Representatives, the most of any state, while Wyoming has one at-large seat. Population also drives demand for housing, transportation, water, and public services, making accurate counts essential for planning and policy.

“California, the most populous state, contains more people than the 21 least populous states combined.” — U.S. Census Bureau analysis of 2020 census data

Methodology

The U.S. Census Bureau produces state population estimates using a cohort-component method. This method starts with the most recent decennial census count (April 1, 2020) and then adds births, subtracts deaths, and adds net migration (both domestic and international) for each year. The estimates are updated annually and released as a “vintage.” The Vintage 2025 estimates cover July 1, 2020, through July 1, 2025, and are the most recent complete set of state population figures.

The national Population Clock, by contrast, provides a real-time estimate based on the latest available data on births, deaths, and net international migration. As of August 19, 2026, the clock showed a U.S. population of 342,775,411.

Limitations of the Data

State population estimates are not exact counts; they are modeled figures that can be revised as new data become available. The decennial census remains the gold standard, but it occurs only every ten years. Annual estimates may undercount or overcount certain groups, particularly international migrants and people in group quarters. Additionally, the 2025 state estimates and the 2026 national clock figure are not directly comparable because they refer to different dates and methodologies.

For the most precise state-level comparison, users should refer to the Census Bureau’s Vintage 2025 state population totals, which are consistent across all states and the District of Columbia.

Source & Data Date

Primary source: U.S. Census Bureau, Population Estimates Program — Vintage 2025 state population totals, released January 2026, covering April 1, 2020, to July 1, 2025. National population figures are from the U.S. Census Bureau Population Clock, accessed August 20, 2026. Additional context from the Census Bureau’s 2020 census analysis and Statista’s state population data for 2025.