Early 20th Century

The early years of the 20th century saw a vast expansion in the population and urbanization of Brooklyn. Innovations in transportation, funded by tax dollars from New York City, brought new bridges, trolley lines, elevated railroads, and subway lines that extended farther and farther into the heart of the borough. Trolleys began to traverse the streets of Brooklyn in 1890, the Williamsburg Bridge was completed in 1903, the first subway line was thrust under the East River in 1908, and the Manhattan Bridge opened in 1909. Each expansion opened new areas for settlement and development. The rural character of Brooklyn was quickly vanishing.

By 1880, Brooklyn had evolved into one of the leading producers of manufactured goods in the nation. Brooklyn's largest industry, sugar refining, produced more than half the sugar consumed in the United States. There were also dockyards, gas refineries, ironworks, slaughterhouses, book publishers, sweatshops, and factories producing everything from clocks, pencils, and glue, to cakes, beer, and cigars. Work, though not always safe or healthy, was widely available.

Between World War I and the 1930s, thousands of southern Blacks filtered into Brooklyn's neighborhoods. They were among the hundreds of thousands who moved to northern cities during the "Great Migration," and by 1930, more than 60% of the African Americans in Brooklyn had been born outside the borough. When the A train was extended from Harlem to Brooklyn in 1936, thousands of African Americans left Harlem in search of better lives and less expensive housing. Thousands of Puerto Rican immigrants also settled in Brooklyn. The trip from Puerto Rico took five days by steamship, but offered an alternative to the poverty and limitations of the tiny island. Puerto Ricans settled in Red Hook, downtown Brooklyn, and Greenpoint, and many found jobs in the needle trades and cigar factories.

The stock market crash in 1929 dashed hopes for a prosperous life for many of the new immigrants. Thousands of workers lost their jobs, and breadlines and Salvation Army food stations became familiar sights. The Depression ended with the entry of the United States into World War II, and by the time the soldiers returned, their communities had again begun to change.