Harbor Defenses of the Delaware

Fort DuPont, named in honor of Rear Admiral Samuel Francis Du Pont, is located between the original Delaware City and the modern Chesapeake and Delaware Canal on the original Reeden Point tract, which was granted to Henry Ward in 1675. Along with two other forts of the Harbor Defenses of the Delaware, it defended the Delaware River and the water approach to Philadelphia from 1900 through 1942. In 2016, the acreage which is not in the state park system was annexed into Delaware City. The first fortification built was the Ten Gun Battery, an auxiliary to nearby Fort Delaware during the American Civil War. The Twenty Gun Battery was constructed on the reservation during the 1870s, later followed by a mine control casemate for an underwater minefield in 1876. In 1897-1904, Endicott-era emplacements were constructed for long-range rifles, mortars, and rapid-fire guns. In 1922 the post became headquarters for the 1st Engineer Regiment, which remained at the post until 1941. During World War II, Fort DuPont served as a mobilization station for deploying units, and contained a prisoner-of-war camp for captured German soldiers and sailors. After the war, Fort DuPont was declared surplus and offered to the Veterans Administration for use as a veterans hospital. After they declined, the state bought the site at a 100 percent discount and adapted existing structures for reuse. In 1948, it officially opened as the Governor Walter W. Bacon Health Center. In 1992 a portion was redesignated as Fort DuPont State Park, which became Delaware's 13th state park. In 1999 the site was officially designated the Fort DuPont Historic District after it was listed in the National Register of Historic Places. The historic district comprises Fort DuPont State Park and the Governor Bacon Health Center. The site is currently being redeveloped by the Fort DuPont Redevelopment and Preservation Corporation.

Fort DuPont State Park is a Delaware state park located in Delaware City, Delaware. Fort DuPont itself, named after Rear Admiral Samuel Francis duPont, was used as a military base from the Civil War through World War II, and was part of a three fort defense system along with Fort Delaware and Fort Mott, with the purpose of protecting the Delaware River and the city of Philadelphia from naval attacks from 1897 through 1942. Fort DuPont State Park is situated along the Delaware River and Chesapeake and Delaware Canal.

Delaware City is a city in New Castle County, Delaware, United States. The population was 1,885 as of 2020. It is a small port town on the eastern terminus of the Chesapeake and Delaware Canal and is the location of the Forts Ferry Crossing to Fort Delaware on Pea Patch Island.

Delaware City Historic District is a national historic district located at Delaware City, New Castle County, Delaware. It encompasses 204 contributing buildings and 1 contributing site in the town of Delaware City. The buildings were built between about 1826 and 1930. They are primarily residential buildings, with some commercial and institutional buildings including notable examples of the Greek Revival and Italianate styles. Notable buildings include the Delaware City Hotel (1828), Central Hotel (c. 1835), Christ Episcopal Church (1849) and Rectory (1870), Van Hekle House (1828), Delaware City Academy (1858), Delaware City Public School (1883), Dunlap/Worrell House (c. 1826), and First Presbyterian Church (c. 1835).It was listed on the National Register of Historic Places in 1983.

Chelsea is a historic home located in Delaware City, New Castle County, Delaware. It was built in 1848 by Thomas Clark, and is a three-story, three-bay-square brick block with a low, almost flat, hipped roof surmounted by a widow's walk. It is in a regional variation of the Italianate / Greek Revival style. It has a low, one-story wing at the east side, a wide, one-story glass-enclosed front porch and a large, two-story addition to the rear of the house.It was listed on the National Register of Historic Places in 1982.

Fort Delaware is a former harbor defense facility, designed by chief engineer Joseph Gilbert Totten and located on Pea Patch Island in the Delaware River. During the American Civil War, the Union used Fort Delaware as a prison for Confederate prisoners of war, political prisoners, federal convicts, and privateer officers. A three-gun concrete battery of 12-inch guns, later named Battery Torbert, was designed by Maj. Charles W. Raymond and built inside the fort in the 1890s. By 1900, the fort was part of a three fort concept, the first forts of the Coast Defenses of the Delaware, working closely with Fort Mott in Pennsville, New Jersey, and Fort DuPont in Delaware City, Delaware. The fort and the island currently belong to the Delaware Department of Natural Resources and Environmental Control (DNREC) and encompass a living history museum, located in Fort Delaware State Park.

Pea Patch Island is a small island, approximately 1 mi (1.6 km) long, in the U.S. state of Delaware, located in the mid channel of the Delaware River near its entrance into Delaware Bay. It is a low, marshy island, located in New Castle County, facing Delaware City on the Delaware shore, and Finns Point on the New Jersey shore. Once the location of strategic military defenses, the island is currently owned by the State of Delaware as Fort Delaware State Park. The island emerged as a mud bank in the river in the 18th century. According to folklore, the island received its name after a ship full of peas ran aground on it, spilling its contents and leading to a growth of the plant on the island. In the 1790s, Pierre L'Enfant suggested the use of the island as part of the defenses of New Castle, Delaware and Philadelphia. During the War of 1812, a seawall and dykes were built on the island, with a view to building a Martello tower there. By 1814, the island had been sufficiently developed for the construction of the first Fort Delaware. A five-pointed star fort was built 1815–1824. However, this fort was wrecked by a fire in 1831. Construction began on a much larger polygonal fort in 1836, but this project was derailed by a decade-long legal battle over which state owned the island, which was won by Delaware. Construction then began in 1848 on the current fort, with an irregular pentagon design about the size of the previous star fort. The fort was substantially complete by 1860. During the American Civil War, Fort Delaware was used by the Union as a camp for Confederate prisoners, in particular ones captured at the 1863 Battle of Gettysburg. Many of the prisoners and some guards who died at the fort are buried at nearby Finns Point National Cemetery in New Jersey. Around the turn of the century, a large battery for three then-modern 12-inch guns on disappearing carriages was built in the fort as part of the Endicott program, with batteries for smaller guns elsewhere on the island. On the shores flanking the island, Fort DuPont and Fort Mott were built with modern weapons, and preparations were made to lay underwater minefields in the river. The defenses around Pea Patch Island were disarmed during World War II, as Fort Miles at the mouth of the Delaware estuary superseded them. In the early 20th century, the U.S. Army Corps of Engineers dredged a channel around the island, using the infill to double the island's size on its northern end. The island is publicly accessible by ferry from both the Delaware and New Jersey banks. In addition to the historic features of the state park, the island provides a significant wetlands stop for migratory birds along the Atlantic Flyway. It is the location of the largest colony of herons in the U.S. north of Florida.

Fort Delaware State Park is a 288-acre (117 ha) Delaware state park on Pea Patch Island in New Castle County, Delaware. A fortress was built on Pea Patch Island by the United States Army in 1815, near the conclusion of the War of 1812, to protect the harbors of Wilmington, Delaware and Philadelphia, Pennsylvania. The fort was burned and rebuilt in the years prior to the American Civil War, and soon after the start of the war the fort was converted to a Prisoner of War camp. Fort Delaware continued to protect the mouth of the Delaware River through World War I and II. Pea Patch Island and Fort Delaware was declared surplus land by the United States Department of Defense in 1945. Fort Delaware State Park, one of the first state parks in Delaware, was established in 1951. The park, which can only be accessed by ferry, is open for historic programs at Fort Delaware. The fort is listed on the National Register of Historic Places. In addition to historical preservation, Fort Delaware State Park is also open for picnicking and hiking. Visitors to the park may reach it by ferry from Delaware City or Fort Mott State Park in New Jersey. Fort Delaware State Park is 0.5-mile (800 m) from Delaware City via the Forts Ferry Crossing. Passengers aboard the ferry are granted access to Fort Mott State Park.

Fairview is a historic home located near Delaware City, New Castle County, Delaware. It was built in 1822 as a two-story, five-bay rectangular brick dwelling with a Georgian style, center hall plan. It was modified in 1880 by architect Frank Furness to add a shingled third story, four notable corbeled chimneys, and an addition.It was listed on the National Register of Historic Places in 1982.

Windsor, also known as Annondale, is a historic home located near Port Penn in New Castle County, Delaware, USA. It was built about 1760, and is a two-story, five-bay, gable-roof, brick building with interior brick chimneys at each gable end. It has a center-passage plan with overall dimensions of 45 feet wide by 19 feet deep. A two-story, wood-frame kitchen wing abuts the rear of the main house. The front facade features a hipped-roof frame porch added in the late-19th century. It is in the Federal style.It was listed on the National Register of Historic Places in 1992.

Ashton Historic District is a national historic district located near Port Penn, New Castle County, Delaware, United States. It encompasses six contributing buildings associated with an original settler and his immediate descendants on early land grant in St. Georges Hundred. The three structures associated with the early occupation are the Robert Ashton House, the Joseph Ashton House, and the John Ashton House. The Robert Ashton House, probably the earliest of the group, is a frame, five-bay, single-pile, gambrel-roofed building with shed-roofed dormers. The Joseph Ashton House, consists of an early-18th-century two-story, three-bay, hall-and-parlor-plan brick structure with a late-18th or early-19th century brick wing. The John Ashton House, consists of a brick, early-18th century two-story, three-bay, hall-and-parlor-plan house with a frame wing.It was listed on the National Register of Historic Places in 1978.

Finns Point is a small promontory in Pennsville Township, Salem County, New Jersey, and New Castle County, Delaware, located at the southwest corner of the cape of Penns Neck, on the east bank of the Delaware River near its mouth on Delaware Bay. Due to the wording of the original charter defining the boundaries of New Jersey and Delaware, part of the promontory is actually enclosed within the state of Delaware's border, due to tidal flow and the manner in which the borders between New Jersey and Delaware were first laid out. Therefore, this portion of Finns Point, also called The Baja, is an exclave of Delaware, cut off from the rest of the state by Delaware Bay. The area is about 10 miles (16 km) south of the city of Wilmington, and directly across the Delaware River from the New Castle area, and the Delaware River entrance to the Chesapeake & Delaware Canal. Pea Patch Island, part of the state of Delaware, sits in the channel of the river facing the promontory. The area in Delaware was previously protected as Killcohook National Wildlife Refuge but is now a confined disposal facility used by the U.S. Army Corps of Engineers.