Kanadesaga was built in 1756, in Ontario County, in Geneva, at the foot of Seneca Lake. The fortification featured four walls each one hundred feet in length, which stood fifteen feet high, and boasted two fifteen-foot square-shaped blockhouses at the diagonals. Built for the Native American settlement of Kanadesaga, which served as a hub of the Seneca tribe. The fort was destroyed in 1779, during the American Revolution.

Kenisico Nike Base, also known as “NY-09”, was opened in 1955 and served as an IFC Area, as well as a missile launch outpost in White Plains, New York. The base was closed down after just eight years of operation in 1963. Between 1959 and 1963, it was manned by NYARNG units under ARADCOM.

The Kenneth A. Kesselring Site, located in West Milton, Saratoga County, was established in 1957 as one of two Navy training sites for nuclear reactor operators. At its peak, the site had four active nuclear reactors, but two were decommissioned in the 1990s, leaving only two reactors in operation. Today, around 800 sailors are trained at Kesselring annually, a decrease from the 2,000 trained during the 1980s. In addition to the sailors, the site also employs around 500 naval personnel and 400 civilians in training or support roles. The Kesselring site is operated by the Knolls Atomic Power Laboratory (KAPL), located in Schenectady, which is solely engaged in research and development for designing and operating naval nuclear propulsion plants. All activities at the Kesselring site relating to naval nuclear propulsion systems are performed in accordance with the requirements and authority of the Naval Nuclear Propulsion Program, a joint program between the Department of Energy and the U.S. Department of Navy. The site is also used for full-scale testing of propulsion plant prototype hardware and for training of personnel.

Fort Kentucky, also known as Fort Mud, was built in Sackets Harbor and was active from 1812 to 1815, during the War of 1812. It served as a minor redoubt, and was equipped with twenty guns, and was one of four similar defensive positions in a fortified line, the others being Fort Virginia, Fort Chauncey, and Fort Stark. The line of forts was anchored at Fort Pike on the bay, which was later known as Madison Barracks, and was intended to protect the land near Sackets Harbor. The site of Fort Kentucky can be found on what is now the south side of Washington Street, almost on the shore of the lake.

Fort Keyser: 1750, Stone Arabia, Montgomery County. Stone house of Johannes Keyse, loop-holed with fortifications added 1776. No longer used when Fort Paris built 1/2 mile north in spring 1777. Building was torn down in 1840s.

Fortress of Kienuka: 1500-1640, Lewiston, Niagara County. Squawkihaws and Senecas fort of refuge, located on the Niagara escarpment. Protected by a moat/ditch on the East, West, and South sides, with upright poles of 10 or 12 feet, enclosing a space of about 20 by 50 rods.

Fort Kimber: 1759, Orange County, Uniondale. Built by George Kimber, a miller, during the French and Indian War.

King's Bridge Redoubt: 1775, New York City. Site of King's Bridge over Spuyten Duyvil Creek for Old Post Road to the Bronx. No information on the American works, the British built a semicircular earthwork in November 1776. Location was about 230th Street and Broadway. The creek was filled in 1913.

King's Ferry Forts: Kings Ferry ran from the West side of the Hudson River at Stony Point to the East side of the River at Verplank's Point, protected by Fort Lafayette (1).

King's Redoubt: 1776, British, New York City, with an abatis added in 1778. Adjacent to Fort Number 7, and probably torn down at the same time in September 1779. Used in attack on Fort Washington.

Fort Klock: 1750, St Johnsville, Mongomery County. An L-shaped, story and half stone house with loopholes built by Johannes Klock. Located on Route 10, on the north bank of the Mohawk, one mile east of St Johnsville center and 3/4 miles south of Fort Hess. Fort Klock was restored and is open as a museum. Battle of Klock's Field, October 19, 1780, was just east of the Fort.

(1) 1777, St. George, Staten Island. An British earthen redoubt on Fort Hill. Repelled an American assault in January 1780. (2) 1776, British rename of Fort Washington, November. Reverted to Fort Washington after Americans reoccupied NYC upon the British withdrawl.