The American Community Survey (ACS) and the Puerto Rico Community Survey (PRCS) ask respondents aged 1 year and over whether they lived in the same residence 1 year ago. For people who lived in a different residence, the location of their previous residence is collected. ACS uses a series of monthly samples to produce estimates. The state-to-state migration flows are created from tabulations of the state of current residence crossed by state of residence 1 year ago (including the District of Columbia and Puerto Rico).

State-to-state migration flows are available starting with the 2005 ACS.

Sample size and data quality measures, including coverage rates, allocation rates, and response rates, are available on the American Community Survey (ACS) Research & Methodology page.

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 a margin of error. The tables on this page include 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 Accuracy of the Data. The effect of nonsampling error is not represented in these tables.

After the release of the 2022 State-to-State Migration Flows, a processing error was identified among respondents who reported moving within the state of Connecticut or from the state of Connecticut to another state or Puerto Rico. For Connecticut as a state of current or previous residence, users should not compare the 2022 one-year state-to-state migration flow estimates to estimates from other years. For other states and Puerto Rico, users should use caution when comparing 2022 one-year state-to-state migration flow estimates to estimates from other years. The processing error affecting 2022 estimates has been corrected for the 2023 State-to-State Migration Flows. For more information, visit: https://www.census.gov/programs-surveys/acs/technical-documentation/errata/143.html

Due to hurricanes, data collection activities in Puerto Rico were disrupted from September through December of 2017. All 2017 one-year estimates for Puerto Rico are based on data collected prior to this disruption. For more information, visit: https://www.census.gov/programs-surveys/acs/technical-documentation/user-notes/2018-02.html