A timeline of United States inventions (1890–1945) encompasses the innovative advancements of the United States within a historical context, dating from the Progressive Era to the end of World War II, which have been achieved by inventors who are either native-born or naturalized citizens of the United States. Copyright protection secures a person's right to the first-to-invent claim of the original invention in question, highlighted in Article I, Section 8, Clause 8 of the United States Constitution which gives the following enumerated power to the United States Congress:

In 1641, the first patent in North America was issued to Samuel Winslow by the General Court of Massachusetts for a new method of making salt.James W. Cortada, "Rise of the knowledge worker, Volume 8 of Resources for the knowledge-based economy", Knowledge Reader Series, Butterworth-Heinemann, 1998, p. 141, , ."Manufactures of the United States in 1860; compiled from the original returns of the eighth census, under the direction of the Secretary of the interior", Publisher: Government Printing Office, Washington, 1865, p. cxcix: "Salt-making was commenced at Salein in 1636, and in 1641 Samuel Winslow was allowed, for 10 years, the exclusive right of making salt in Massachusetts by a new method." On April 10, 1790, President George Washington signed the Patent Act of 1790 (1 Stat. 109) into law which proclaimed that patents were to be authorized for "any useful art, manufacture, engine, machine, or device, or any improvement therein not before known or used." On July 31, 1790, Samuel Hopkins of Philadelphia, Pennsylvania, became the first person in the United States to file and to be granted a patent under the new U.S. patent statute. The Patent Act of 1836 (Ch. 357, 5 Stat. 117) further clarified United States patent law to the extent of establishing a patent office where patent applications are filed, processed, and granted, contingent upon the language and scope of the claimant's invention, for a patent term of 14 years with an extension of up to an additional seven years.

From 1836 to 2011, the United States Patent and Trademark Office (USPT) granted a total of 7,861,317 patents relating to several well-known inventions appearing throughout the timeline below. Some examples of patented inventions between the years 1890 and 1945 include John Froelich's tractor (1892), Ransom Eli Olds' assembly line (1901), Willis Carrier's air-conditioning (1902), the Wright Brothers' airplane (1903), and Robert H. Goddard's liquid-fuel rocket (1926).

Progressive Era (1890–1919)

1890 Stop sign A stop sign is a traffic sign, usually erected at road junctions such as a four-way intersection, that instructs drivers to stop and then to proceed only if the way ahead is clear. The idea of placing stop signs at road junctions was first conceived in 1890 when William Phelps Eno of Saugatuck, Connecticut, proposed and devised the first set of traffic laws in an article published in Rider and Driver. However, the first use of stop signs did not appear until 1915 when officials in Detroit, Michigan, installed a stop sign with black letters on a white background. Throughout the years and with many alterations made to the stop sign, the current version with white block-lettering on a red background that is used in the United States as well as emulated in many other countries around the world today, did not come into use until the Joint Committee on Uniform Traffic Control Devices adopted the design in 1954.

1890 Tabulating machine The tabulating machine is an electrical device designed to assist in summarizing information and, later, accounting. The results of a tabulation are electrically coupled with a sorter while displayed on clock-like dials. The concept of automated data processing had been born. In 1890, Herman Hollerith invented the mechanical tabulating machine, a design used during the 1890 Census which stored and processed demographic and statistical information on punched cards.

1890 Shredded wheat Shredded wheat is a type of breakfast cereal made from whole wheat. Shredded wheat also comes in a frosted variety, which has one side coated with sugar and usually gelatin. Shredded wheat was invented in 1890 by Henry Perky of Watertown, New York.

1890 Babcock test The Babcock test was the first inexpensive and practical test which were used to determine the fat content of milk. Invented by Stephen Moulton Babcock in 1890, the test was developed to prevent dishonest farmers who could, until the 1890s, water down their milk or remove some cream before selling it to the factories because milk was paid by volume.

1890 Smoke detector A smoke detector is a device that detects smoke and issues a signal. Most smoke detectors work either by optical detection or by physical process, but some of them use both detection methods to increase sensitivity to smoke. Smoke detectors are usually powered by battery while some are connected directly to power mains, often having a battery as a power supply backup in case the mains power fails. The first automatic electric fire alarm was co-invented in 1890 by Francis Robbins Upton and Fernando J. Dibble. Upton and Dibble were issued U.S. patent #436,961. Upton was an associate of Thomas Alva Edison, although there is no evidence that Edison contributed to this invention.

1891 Incandescent lamp One of the most dramatic improvements occurred in artificial lighting. Thomas Edison's is credited with the first practical incandescent lamp which made lighting more practical for factories, offices, and homes, and transformed city life.

1891 Ferris wheel

A Ferris wheel is a non-building structure, consisting of an upright wheel with passenger gondolas attached to the rim. Opened on June 21, 1893, at the Chicago World's Fair, the original Ferris wheel was invented two years earlier by the Pittsburgh bridge-builder George Washington Gale Ferris Jr. in 1891.

1891 Dow process The Dow process is the electrolytic method of bromine extraction from brine, and was Herbert Henry Dow's second revolutionary process for generating bromine commercially in 1891.

1891 Tesla coil A Tesla coil is a type of resonant transformer circuit invented by Nikola Tesla around 1891. Nikola Tesla used these coils to conduct innovative experiments in electrical lighting, phosphorescence, x-ray generation, high frequency alternating current phenomena, electrotherapy, and the transmission of electrical energy without wires for point-to-point telecommunications, broadcasting, and the transmission of electrical power.

1891 Rotary dial The rotary dial is a device mounted on or in a telephone or switchboard that is designed to send electrical pulses, known as pulse dialing, corresponding to the number dialed. The early form of the rotary dial used lugs on a finger plate instead of holes. The rotary dial was invented by Almon Brown Strowger in 1891. Strowger filed U.S. patent#486,909 on December 21, 1891, that was later issued on November 29, 1892.

1891 Pastry fork A pastry fork, also known as a "pie fork", is a fork designed for eating pastries and other desserts while holding a plate. The fork has 3 or 4 tines. The 3 tine fork has a larger, flattened and beveled tine on the side while the 4 tine fork has the 1st and 2nd tine connected or bridged together and beveled. On July 7, 1891, Anna M. Mangin of Queens, a borough of New York City, filed the first patent for the pastry fork. U.S. patent #470,005 was later issued on March 1, 1892.

1891 Schrader valve A Schrader valve consists of a hollow cylindrical metal tube, typically brass, with the exterior end threaded. The interior end takes a variety of forms depending on its application. In the center of the exterior end is a metal pin pointing along the axis of the tube; the pin's end is flush with the end of the valve body. Generally, all Schrader valves are used on tires. They have threads and bodies of a single standard size at the exterior end, so caps and tools generally are universal for the valves on all automobile and bicycle pneumatic tires. Also, pressure valves can be used on Schrader valves in place of caps in order to measure the pressure of pneumatic tires. In 1891, George Schrader, the son of German-American immigrant August Schrader, invented the Schrader valve. A patent was issued on April 11, 1893.

1892 Bottle cap Bottle caps, or closures, are used to seal the openings of bottles of many types. They can be small circular pieces of metal, usually steel, with plastic backings, and for plastic bottles a plastic cap is used instead. Caps can also be plastic, sometimes with a pour spout. Flip-Top caps like Flapper closures provide controlled dispensing of dry products. The crown cork, the first form of a bottle cap, possessed flanges bent over a sealed bottle to compress the liquid inside. It was invented and patented in 1892 by William Painter of Baltimore, Maryland.

1892 Dimmer Dimmers are devices used to vary the brightness of a light. By decreasing or increasing the RMS voltage and hence the mean power to the lamp it is possible to vary the intensity of the light output. Although variable-voltage devices are used for various purposes, a dimmer is specifically those devices intended to control lighting. Dimmers are popularly used in venues such as movie theatres, stages, dining rooms, restaurants, and auditoriums where the need or absence of light during activities requires constant change. The dimmer was invented in 1892 by Granville Woods.

1892 Bicycle seat (padded) A bicycle seat, unlike a bicycle saddle, is designed to support the rider's buttocks and back, usually in a semi-reclined position. First known as the "Garford Saddle", the padded bicycle seat was invented in 1892 by Arthur Lovett Garford of Elyria, Ohio.

1892 internal combustion-powered tractor A tractor is a distinctive farm vehicle specifically designed to deliver a high tractive effort at slow speeds, for the purposes of hauling a trailer or machinery used in agriculture or construction. Agricultural implements may be towed behind or mounted on the tractor, and the tractor may also provide a source of power if the implement is mechanized. While steam powered tractors had been built earlier, In 1892, John Froelich invented and built the first gasoline-powered tractor in Clayton County, Iowa.

1893 Zipper

The zipper is a popular device for temporarily joining two edges of fabric. Zippers are found on trousers, jeans, jackets, and luggage. Whitcomb L. Judson was an American mechanical engineer from Chicago who was the first to invent, conceive of the idea, and to construct a workable zipper. Using a hook-and-eye device, Judson intended for this earliest form of the zipper to be used on shoes. He also conceived the idea of the slide fastener mechanism in conjunction with the invention of the zipper. Patents were issued to Judson for the zipper in 1891, 1894, and 1905.

1893 Spectroheliograph The spectroheliograph is an instrument used in astronomy that captures a photographic image of the Sun at a single wavelength of light, a monochromatic image. The spectroheliograph was invented in 1893 by George Ellery Hale and independently later by Henri Alexandre Deslandres in 1894.

1893 Pinking shears Pinking shears are a type of scissors that have blades of which are sawtoothed instead of straight. Used to cut woven cloth, pinking shears leave a zigzag pattern instead of a straight edge. The earliest patent for pinking shears was U.S. patent #489,406 which was issued to Louise Austin of Whatcomb, Washington, on January 3, 1893.

Early 1890s Phantoscope A film projection machine created by Charles Francis Jenkins in the early 1890s. Jenkin's machine was the first projector to allow each still frame of the film to be illuminated long enough before advancing to the next frame sequence.Tube – The Invention of Television, David E. Fisher and Marshal Jon Fisher, 1996