Since 1950, Americans have increasingly chosen to live in cities. Today, 81% live in urban areas, more than even before. Urban areas, however, make up just 3% of U.S. land area.

The proportion of people living in urban areas varies considerably between states. 24/7 Wall St. reviewed data from the U.S. Census to determine the states with the highest shares of residents who live in cities. In California, 95% of the population lives in urban areas, the highest share of any state. Only 39% of Maine’s population lives in cities, the lowest share in the country.

Many factors influence the decision where to live, but job opportunities are often the most important. Job opportunities in urban areas are different than in rural ones. While dense cities are often business hubs, employing highly skilled labor such as scientists and engineers as well as business executives, jobs in rural areas are based on farming and mining, require less training, and are often lower paying. College graduates therefore gravitate to large cities, while Americans with less education tend to move to rural areas where the cost of living is lower.

Click here to see how many people live in cities in each state.

States with higher educational attainment rates generally have higher percentages of the population living in urban areas and higher median household incomes. Of the 10 states with highest rates of city living, eight have median household incomes higher than the national median. In contrast, none of the 10 states with the lowest percentage of population living in urban areas have a median income greater than the national median. However, all 10 have a cost of living lower than the national average.

To identify the states where the highest share of people live in cities, 24/7 Wall St. examined urban and rural population, population density, and land area by state from the 2010 Decennial Census. Median household incomes and educational attainment rates come from the U.S. Census Bureau’s 2010 American Community Survey. An urban area, as defined by the U.S. Census Bureau, must encompass at least 2,500 people and have a densely settled core.