Because the city of Newport and its sheltered harbor are on and defined by Aquidneck Island, the East Passage was the main area of fortification until the Endicott Period of the late 19th century.

The north end of it is too narrow and shallow for most vessels to pass, and thus it was not heavily fortified until World War II.

The site was first fortified with an earthen battery in 1700, replaced by Fort Anne (named for the reigning Queen of England) in 1702.

In 1764 persons who believed HMS St John was carrying stolen goods from local merchants seized the unmanned Fort George and fired on the ship, which escaped.

[12] The appearance of a French fleet off Newport in mid-1778 caused the British to scuttle some of their own ships in an attempt to block the harbor.

[15] Patriot forces attempted to recover Newport in August 1778, fighting the Battle of Rhode Island about seven miles north of the town, but were unsuccessful.

[12] A year later the French left Rhode Island to join Washington's forces north of New York City, eventually participating in the Yorktown campaign that effectively won the Revolution.

By this time Newport was considered the most important coastal site in New England, with two companies of the Regular Army's Artillerists and Engineers stationed there.

[19] Its naturally well-protected harbor, if seized by an enemy, could serve as a base for land and sea attacks on Boston or New York.

[9] Although heavily fortified locations were not attacked in the War of 1812, the British managed to bypass or suppress the weak defenses at the mouth of Chesapeake Bay and burn Washington, DC.

[9][24] During the Civil War Fort Adams was an important mobilization center, and served as the home garrison of the 15th US Infantry Regiment.

A battery for eleven 10-inch Rodman guns was also built at the south end of the island; it extended in a north–south line and had wide arcs of fire on either side.

Parrott rifles had shown an alarming tendency to burst when fired, so procurement was stopped shortly after the Civil War and they were deployed only in limited quantities.

The Board of Fortifications was convened in 1885 under Secretary of War William Crowninshield Endicott to develop recommendations for a full replacement of existing coast defenses.

Stateside garrisons were drawn down to provide experienced gun crews on the Western Front; the first two regiments designated to operate French-made railway artillery in France (and their brigade headquarters) mobilized at Fort Adams along with other units.

[43] A pair of 4.72-inch Armstrong guns, transferred from Fort Strong in Boston Harbor, were mounted at Sachuest Point in Middletown to guard the Sakonnet River from 1917 to 1919.

[24] References indicate the authorized strength of CD Narragansett Bay in World War I was 32 companies, including 14 from the Rhode Island National Guard.

The 243rd Coast Artillery was the Rhode Island National Guard component of HD Narragansett Bay from 11 July 1924 through 7 October 1944.

[47] Early in World War II numerous temporary buildings were again constructed to accommodate the rapid mobilization of men and equipment.

These included heavy earth-covered concrete bunkers for ammunition and fire control, with the guns protected by open-back shields.

[34] Four 155 mm (6.1 inch) batteries were emplaced in Rhode Island in 1942 to quickly provide some defense at key points.

[34] Five 90 mm gun Anti-Motor Torpedo Boat (AMTB) batteries were built or deployed in the Narragansett Bay area.

[56] Unlike most of the eastern harbor defense commands, fire control towers in Rhode Island were low-profile.

In World War II an Army-Navy harbor entrance control post-harbor defense command post was built at Fort Burnside, resembling a seaside mansion.

The removal of most weapons and an Army-wide shift from a regimental to a battalion-based system meant organizational changes in Rhode Island's defenses.

The latter was the headquarters of a program to re-educate German prisoners with democratic values, one element of which was the German-language newspaper Der Ruf (The Call).

From circa 1960 to 1974 NAVRADSTA Jamestown, a Navy radio facility, operated at the former Fort Burnside with a tower 600 feet (180 m) tall.

In town on the south side of the harbor is a memorial to Rochambeau's landing in Newport; the statue has a duplicate on the Avenue Pierre-Ier-de-Serbie (Peter I of Serbia) in Paris.

Fort Kearny is now the Narragansett Bay Campus of the University of Rhode Island; the batteries are well-preserved and some have been converted as offices.

Parts of two bastions of Fort Hamilton on Rose Island remain, along with at least three World War II 5-inch gun emplacements.