Although the American Community Survey (ACS) produces population, demographic and housing unit estimates, it is the Census Bureau's Population Estimates Program that produces and disseminates the official estimates of the population for the nation, states, counties, cities, and towns and estimates of housing units for states and counties.

Geographic areas are based on the geographic boundaries of the data year. Current year comparisons with past-year estimates are not re-tabulated to the current year's geographies; rather, the comparison is with the existing geography of each data year. Statistically significant change from prior years' estimates could be the result of changes in the geographic boundaries of an area and not necessarily the demographic, social, or economic characteristics. For more information on geographic changes, see: https://www.census.gov/programs-surveys/acs/guidance.html.

Since the 5-year data do not benefit from data quality filtering, comparisons are only made for populations of 5,000 or more.

Supporting documentation on code lists, subject definitions, data accuracy, and statistical testing can be found on the American Community Survey website in the Technical Documentation section.

Sample size and data quality measures (including coverage rates, allocation rates, and response rates) can be found on the American Community Survey website in the Methodology section.

Source: U.S. Census Bureau, 2017-2021 American Community Survey 5-Year Estimates

Data are based on a sample and are subject to sampling variability. The degree of uncertainty for an estimate arising from sampling variability is represented through the use of a margin of error. The value shown here is the 90 percent margin of error. The margin of error can be interpreted roughly as providing a 90 percent probability that the interval defined by the estimate minus the margin of error and the estimate plus the margin of error (the lower and upper confidence bounds) contains the true value. In addition to sampling variability, the ACS estimates are subject to nonsampling error (for a discussion of nonsampling variability, see ACS Technical Documentation). The effect of nonsampling error is not represented in these tables.

The definitions of the metropolitan and micropolitan statistical areas for the 2013 American Community Survey are based on the commuting patterns identified in the 2010 Census. Estimates prior to 2013 are based on the results of the 2000 Census. Statistically significant change from prior years' estimates could be the result of changes in the metropolitan geographic definitions and not necessarily the demographic, social or economic characteristic. For more information, see: Metropolitan and Micropolitan Statistical Areas.

Households not paying cash rent are excluded from the calculation of median gross rent.

Complete plumbing in 2016 and later are not directly comparable to complete plumbing in 2015 and prior years. In 2016, the question about whether the housing unit had a toilet was no longer asked. In 2015 and prior years, the requirements for complete plumbing were running water, a flush toilet and bathtub or shower; in 2016 and later, the requirement for complete plumbing is running water and bathtub or shower.

Telephone service data are not available for certain geographic areas due to problems with data collection of this question that occurred in 2019. Both ACS 1-year and ACS 5-year files were affected. It may take several years in the ACS 5-year files until the estimates are available for the geographic areas affected.

Prior to 2015, if the median, upper, or lower quartile rent was $2,000 or more in a geography, the median, upper, or lower rent displayed as $2,000+. In 2015, the top category for the calculation of median, upper, and lower quartile rent was changed from $2,000 or more to $3,500 or more; consequently, 2015 and later products from the 1 and 5 year ACS files display actual medians, upper, and lower quartiles up to $3,499; $3,500 or more will display as $3,500+.

Prior to 2015, if the median, upper, or lower quartile home value was $1,000,000 or more in a geography, the median, upper, or lower home value rent displayed as $1,000,000+. In 2015, the top category for the calculation of median, upper, and lower quartile home value was changed from $1,000,000 or more to $2,000,000 or more; consequently, in 2015 and later products from the 1 and 5 year ACS files display actual medians, upper, and lower quartiles up to $2,000,000; $2,000,000 or more will display as $2,000,000+.

Prior to 2015, if the median monthly housing costs for owners without mortgages was $1,000 or more in a geography, the median monthly housing costs for owners without mortgages displayed as $1,000+. In 2015, the top category for the calculation of median monthly housing costs for owners without mortgages was changed from $1,000 or more to $1,500 or more; consequently, in 2015 and later products from the 1 and 5 year ACS files display actual medians up to $1,500; $1,500 or more will display as $1,500+.

For the 5 year ACS, 2011-2015 plumbing data for Puerto Rico will not be shown. Research indicates that the questions on plumbing facilities that were introduced in 2008 in the stateside American Community Survey and the 2008 Puerto Rico Community Survey may not have been appropriate for Puerto Rico. New questions resolved the problem by 2013.

Prior to 2021, medians presented in the Comparison Profiles were calculated from inflation-adjusted microdata and household distributions. Data users were not able to match exactly the estimates in the Profile by Inflation-adjusting previous year published estimates using the Consumer Price Index Research Series (CPI-U-RS). Starting in 2021, the method for calculating inflation-adjusted medians changed. Data users should now be able to more closely match the estimates by inflation-adjusting previous year published estimates. For those medians that do match exactly, the difference is due to rounding and should not be off by more than one dollar. For more information see Modification to Calculations of Inflation-Adjusted Dollar-Based Medians in Comparison Profiles .

The 2017-2021 American Community Survey (ACS) data generally reflect the March 2020 Office of Management and Budget (OMB) delineations of metropolitan and micropolitan statistical areas. In certain instances, the names, codes, and boundaries of the principal cities shown in ACS tables may differ from the OMB delineation lists due to differences in the effective dates of the geographic entities.

Estimates of urban and rural populations, housing units, and characteristics reflect boundaries of urban areas defined based on Census 2010 data. As a result, data for urban and rural areas from the ACS do not necessarily reflect the results of ongoing urbanization.

An * indicates that the estimate is significantly different (at a 90% confidence level) than the estimate from the most current year. A "c" indicates the estimates for that year and the current year are both controlled; a statistical test is not appropriate. A blank indicates that the estimate is not significantly different from the estimate of the most current year, or that a test could not be done because one or both of the estimates is displayed as "-", "N", or "(X)", or the estimate ends with a "+" or "-". (For more information on these symbols, see the Explanation of Symbols.)

Explanation of Symbols:

-	The estimate could not be computed because there were an insufficient number of sample observations. For a ratio of medians estimate, one or both of the median estimates falls in the lowest interval or highest interval of an open-ended distribution. For a 5-year median estimate, the margin of error associated with a median was larger than the median itself.
N	The estimate or margin of error cannot be displayed because there were an insufficient number of sample cases in the selected geographic area.
(X)	The estimate or margin of error is not applicable or not available.
median-	The median falls in the lowest interval of an open-ended distribution (for example "2,500-")
median+	The median falls in the highest interval of an open-ended distribution (for example "250,000+").
**	The margin of error could not be computed because there were an insufficient number of sample observations.
***	The margin of error could not be computed because the median falls in the lowest interval or highest interval of an open-ended distribution.
*****	A margin of error is not appropriate because the corresponding estimate is controlled to an independent population or housing estimate. Effectively, the corresponding estimate has no sampling error and the margin of error may be treated as zero.