The median divides the income distribution into two equal parts, one having incomes above the median and the other having incomes below the median.
U.S. Census Bureau, Small Area Income and Poverty Estimates (SAIPE), https://www.census.gov/programs-surveys/saipe.html
UPDATED - December 2020
NA - Data not available or estimates are unreliable. Estimates are considered unreliable if the relative standard error is greater than 30%.
NOTES - SAIPE uses statistical models to create estimates. The models relate state and county estimates of income and poverty from the American Community Survey (ACS) to other indicators of income and poverty, including federal income tax returns, SNAP benefits data, the most recent decennial census, intercensal population estimates, Supplemental Security Income data, and economic data from the Bureau of Economic Analysis. These estimates are then combined with direct estimates from the ACS sample to provide figures which are more precise than either data set alone, thus providing consistent and reliable single-year estimates. These model-based single-year estimates are more reflective of current conditions than multi-year survey estimates.
LIMITATIONS - Measures of uncertainty for the poverty estimates are provided in SAIPE in the form of 90% confidence intervals. These intervals were constructed from estimated standard errors. For the model-based estimates, the standard error depends mainly on the uncertainty about the model and the ACS sampling variance. Estimates are considered unreliable if the relative standard error is greater than 30%, and unreliable estimates are reported as NA. The 90% confidence intervals for each estimate are available here Median household income.