Across the country, the income gap between blacks and whites remains wide, and nowhere more so than in Manhattan. But just a river away, a very different story is unfolding.

In Queens, the median income among black households, nearing $52,000 a year, has surpassed that of whites in 2005, an analysis of new census data shows. No other county in the country with a population over 65,000 can make that claim. The gains among blacks in Queens, the city’s quintessential middle-class borough, were driven largely by the growth of two-parent families and the successes of immigrants from the West Indies. Many live in tidy homes in verdant enclaves like Cambria Heights, Rosedale and Laurelton, just west of the Cross Island Parkway and the border with Nassau County.

David Veron, a 45-year-old lawyer, is one of them. He estimates that the house in St. Albans that he bought with his wife, Nitchel, three years ago for about $320,000 has nearly doubled in value since they renovated it. Two-family homes priced at $600,000 and more seem to be sprouting on every vacant lot, he says.

“Southeast Queens, especially, had a heavy influx of West Indian folks in the late 80’s and early 90’s,” said Mr. Veron, who, like his 31-year-old wife, was born on the island of Jamaica. “Those individuals came here to pursue an opportunity, and part of that opportunity was an education,” he said. “A large percentage are college graduates. We’re now maturing and reaching the peak of our earning capacity.”