Median household incomes on Long Island remain far above those for the state and the nation, and the region has lower poverty rates as well, according to U.S. Census Bureau data for 2015 released Thursday.

Nassau County’s median household income was $101,830 and Suffolk County’s was $88,340 in the agency’s 2015 American Community Survey, which includes information for areas of the nation with populations of 65,000 and up. New York State’s median was $60,850, while the nation’s was $56,516.

Nassau’s median income ranked first and Suffolk’s was third in the ranking of 39 New York counties that met the population threshold for inclusion. The state has 62 counties.

The survey data for the Island, for the most part, did not mirror the year-to-year change in national data that the bureau released Tuesday, which gave statistics from 2014 to 2015 in income, poverty and health insurance.

For example, the Census reported a 5.2 percent rise in the nation’s median household income from 2014 to 2015 — the first increase since 2007 and one of the largest annual gains since 1967 to 1968.

Nassau saw median incomes rise over longer periods of two, three and four years that the bureau said were statistically significant. In 2011, for example, the county’s median income was $96,296.

In Suffolk, however, median income over the same time span remained flat. Suffolk’s 2011 median of $88,435 was essentially unchanged in 2015.

The counties also diverged in their poverty rates.

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Nassau and Suffolk ranked third and fourth, respectively, in having the lowest poverty rates among the 39 New York counties included in the survey. The state’s 2015 poverty rate was 15.4 percent.

Nassau’s poverty rate dropped from 6.4 percent to 5.8 percent from 2014 to 2015, a change the bureau said wasn’t statistically significant. When looked at over a longer period, though, the county has registered a decline in poverty since 2011, when the rate was 6.8 percent.

Suffolk’s poverty rate was 7.6 percent in 2015, not much different from the 7.4 percent in 2014, according to the census report. In 2011, the county’s poverty rate was 6.4 percent.

Jan Vink, a researcher with Cornell University’s Program on Applied Demographics, which is a coordinating agency with the State Data Center, speculated that a sampling error could explain Suffolk’s poverty rate increase.

“If you plot all the years, you see some up and down,” he said, adding, “You could over-sample people with low income in one year.”

The American Community Survey data showed that 5.4 percent of people in Nassau and 5.9 percent in Suffolk in 2015 didn’t have health insurance.

Suffolk showed a statistically significant drop in those without coverage since 2014, when 7.6 percent were without coverage. There was no statistically significant change in that period for Nassau.

Both counties showed big drops in the percentage of the uninsured since 2011, when 8.7 percent of people in Nassau didn’t have health insurance and 9.8 percent in Suffolk were without it.

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One local advocate said the “big picture is good news,” speaking of the national trends. But she had concerns.

“For us as a region, we need to look at all of the components that come into play when you talk about an individual’s financial situation,” said Gwen O’Shea, president and CEO of the Health and Welfare Council of Long Island, an umbrella agency for more than 300 health and human service providers. She said “the lack of affordable housing and public transportation, coupled with the high cost of living, creates many barriers” for those in poverty.