A number of advancements in American manufacturing technology increased the productivity of American industries. Many took place in New England, or were initiated by New Englanders. Among these advancements were Evans' work with flour mills; Whitney's invention of the cotton 'gin and establishment of a new manufacturing method; Lowell's and Slater's work with cotton mills and du Pont's gunpowder mills.

Oliver Evans, an inventor from Delaware, applied his skills to improving the technology used in water-powered flour mills. He invented the elevator, the conveyer, the drill, the hopper-boy and the descender, which revolutionized the way in which flour mills were constructed and used. In 1786-87, Maryland and Pennsylvania gave Evans exclusive rights to apply his flour-mill inventions in their states.

Eli Whitney, a New England teacher who had studied mechanics, invented the cotton 'gin in 1793. The simple machine allowed one person to separate the seeds from cotton much more quickly than ever before. This allowed cotton plantations to produce a great deal more cotton with the same amount of labor. Unfortunately, the new profitability of the industry gave slaveowners more incentive to maintain the institution of slavery. The cotton industry, prevalent in some parts of the South, grew tremendously.

The cotton industry in New England also grew in the early national period, largely due to the efforts of Samuel Slater and Francis Lowell, both of whom brought British textile technology to the United States. Samuel Slater, an Englishman, became interested in going to the US when Congress passed an act in 1789 to encourage manufactures. However, English law did not allow him to take any drawings or models with him. He solved the problem by memorizing the complex plans needed to build the cotton mill machinery. Slater landed in New York in November, 1789. After he heard that Moses Brown in Rhode Island had made some attempts at cotton-spinning, Slater contacted him. Brown replied, "If thou canst do this thing, I invite thee to come to Rhode Island, and have the credit of introducing cotton-manufacture into America." When he arrived in Rhode Island in January of 1790, he entered an agreement with William Almy and Smith Brown to build and operate a cotton-spinning machine. By the end of the year, the machines were ready, all designed by Slater himself. Slater trained others in how to operate the machinery, using child labor to run the mills. Soon the machines were producing cotton at a quality level equal to British textiles.

Slater's mills were only moderately successful until the Napoleonic Wars in Europe limited the importation of cotton. The Embargo Act of 1808, which limited foreign trade, further contributed to an increase in demand for domestic cotton. The ensuing demand spurred on Slater's business. In addition, while there had been only 15 mills in the US in 1808, there were 87 more by the end of 1809.

Francis Lowell further improved upon the technology of the American cotton manufacturing industry. During a trip to England for health reasons, Lowell observed the textile mills of Lancashire, and was impressed by them. Upon his return to the US in 1812, he joined Nathan Appleton and his brother-in-law, Patrick Jackson, to found the Boston Manufacturing Company in Waltham, Massachusetts. He combined what he remembered from Lancashire with the mechanical guidance of Paul Moody. The factory they built was the first to include all stages of cotton manufacturing in one building. Although Lowell, like Slater, initially used child labor; Lowell stopped the practice and began hiring young ladies, aged 18 to 22. By establishing a well-supervised environment for young ladies, Slater encouraged families to send their daughters to earn some money before they got married. The Lowell Mills became long-term successes, influencing other entrepreneurs to imitate his example.

While Eli Whitney is best remembered for his invention of the cotton 'gin, he also influenced the American economy with his development of a new manufacturing method. The method involved the use of interchangeable parts, a revolutionary idea in the new nation. His gun factory, established in 1798, was the first American factory to use parts made so accurately that part of any one would fit any other. Rather than use skilled gunsmiths, Whitney taught unskilled laborers how to one thing on one gun part. Putting all the laborers together, he was able to assemble guns with great speed and accuracy. Whitney even set up gauges to check the accuracy of the work on each piece. This method of manufacturing, called the "American system" in England, became the foundation for modern mass production.

Another manufacturer who influenced firearms was Eleuthère Irénée du Pont. A Frenchman, he moved to the United States in 1800, and was surprised at the lack of high quality gunpowder available in the new nation. Applying what he had learned as an apprentice with Antoine Lavoisier, the great French chemist, du Pont set up the Elutherian Mills near Wilmington, Delaware, along the Brandywine Creek. In 1801, he received his first business order - a request from President Thomas Jefferson to refine some saltpeter. Although the business was in uncertain financial circumstances for a number of years, du Pont maintained his determination to succeed. He bought up his investors' holdings when they refused to reinvest in improvement and expansion, although this placed him deeply in debt. By 1811, du Pont's mills were the largest of any industry in the United States, and were turning a profit of $45,000.