Spesutie Island

Susquehanna River National Wildlife Refuge is located on a small island 3.79 acres (15,300 m2) in size located at the mouth of the Susquehanna River in Harford County, Maryland. It is a satellite refuge managed by Blackwater National Wildlife Refuge. In the 1920s, the island was used as a fish hatchery to produce such species as shad. In the early 1940s, 13,363 acres (54.08 km2) of water in the Upper Chesapeake Bay were closed by Presidential Proclamations to the hunting of migratory waterfowl. These water areas were designated as the Susquehanna National Wildlife Refuge. At the time of its establishment, the water areas known as the Susquehanna flats were covered with wild celery, pondweeds, redhead grass and other desirable waterfowl foods. Peak waterfowl population numbers included over 500,000 canvasback and redhead ducks and over 200,000 American wigeon. These rich areas of aquatic growth began declining in the 1960s due to changes in the water quality and quantity. Development above the Conowingo Dam caused more rapid drainage and greater water flow through the dam. Currents in the upper Chesapeake Bay deposited heavy loads of silt in the Susquehanna flats area. What remained of the suitable waterfowl vegetation was destroyed when Hurricane Agnes moved through in 1972. Today, only a few thousand geese may be found around the refuge during the winter months. Because of the dramatic decrease in waterfowl numbers and vegetation in the area, the Presidential Proclamations were lifted on September 1, 1978 and the waters were returned to the State of Maryland. Battery Island remains a part of the National Wildlife Refuge System. The refuge has a surface area of 3.79 acres (0.0153 km2; 1.53 ha).

Fishing Battery Light was the last lighthouse constructed in Maryland by John Donahoo. While still standing, it has been supplanted by a steel tower which stands adjacent to it.

The Ballistic Research Laboratory (BRL) was a leading U.S. Army research establishment situated at Aberdeen Proving Ground, Maryland that specialized in ballistics (interior, exterior, and terminal) as well as vulnerability and lethality analysis. BRL served as a major Army center for research and development in technologies related to weapon phenomena, armor, electronic devices, and high-speed computing. In 1992, BRL was disestablished and its mission, personnel, and facilities were incorporated into the newly created Army Research Laboratory (ARL).BRL is perhaps best known for commissioning the creation of ENIAC, the first electronic general-purpose digital computer.

Aberdeen Proving Ground (APG) (sometimes erroneously called Aberdeen Proving Grounds) is a U.S. Army facility located adjacent to Aberdeen, Harford County, Maryland, United States. More than 7,500 civilians and 5,000 military personnel work at APG. There are 11 major commands among the tenant units, including: United States Army Communications-Electronics Command (CECOM) United States Army Combat Capabilities Development Command (CCDC) United States Army Test and Evaluation Command (ATEC) Edgewood Arsenal Adelphi Laboratory Center The Army Reserve Information Operations Command Unified Cross Domain Services Management Office HQ, U.S. Army Contracting Command (Army Contracting Command –APG, Adelphi Contracting Division) U.S Army 93rd Signal Network - Network Enterprise Center Logistics Readiness Center U.S. Army Cyber Operation Group – 335th Signal Command Blossom Point Research Facility

The Combat Capabilities Development Command, (DEVCOM, aka CCDC) (formerly the United States Army Research, Development, and Engineering Command (RDECOM)) is a subordinate command of the U.S. Army Futures Command. RDECOM was tasked with "creating, integrating, and delivering technology-enabled solutions" to the U.S. Army. Headquartered at Aberdeen Proving Ground in Maryland, RDECOM employed more than 13,000 scientists, engineers, researchers, and support personnel working at six major RDE centers and at the U.S. Army Research Laboratory (ARL), providing nearly all of the Army's basic and applied research and development services, including in collaboration with other branches of the armed forces and through a network of more than a thousand academic, industrial, and international partners. CCDC now includes the DEVCOM Analysis Center (formerly ARL/SLAD and AMSAA), and aligns with the top six priorities of AFC: Long Range Precision Fires (LRPF) Next Generation Combat Vehicles (NGCV) Future Vertical Lift (FVL) Army Network Air & Missile Defense Soldier Lethalityas well as Multi-Domain Operations (MDO).

United States Army Materiel Systems Analysis Activity (AMSAA) is an analysis organization of the United States Army. AMSAA's overall goal is to provide soldiers with the best U.S. Army materiel possible. AMSAA supports the U.S. Army by conducting systems and engineering analyses to support decisions on technology, materiel acquisitions, and the designing, developing and sustaining of U.S. Army weapon systems.

The Turkey Point Light is a historic lighthouse at the head of the Chesapeake Bay. Although only a 35-foot (11 m) tower, the 100-foot (30 m) height of the bluffs on which it stands makes it the third highest light off the water in the bay. It is also known for the large number of women who served as lightkeeper.

The Sassafras River is a tributary of the Chesapeake Bay on the Delmarva Peninsula in the United States. It is approximately 22 miles (35 km) long and starts in western New Castle County, Delaware, and along the boundary between Cecil County, Maryland on the north and Kent County, Maryland on the south. It rises southwest of Middletown, Delaware and ends at the Chesapeake Bay in a wide mouth between Howell Point near Betterton, Maryland and Grove Point on Grove Neck. It is south of the Elk River and north of the Chester River. The Sassafras River is entirely within the coastal plain. Its watershed area (including the water surface) is 97 square miles (250 km2), with 83 square miles (210 km2) of land. Thus, its total watershed area is 14% water. There are several small creeks on the northern shore of the Sassafras River, including Money Creek, Cox Creek, Foreman Creek, Back Creek, McGill Creek, Dowdel Creek, Hall Creek, and Duffy Creek. On the southern shore small creeks include Lloyd Creek, Turner's Creek, Freeman Creek, Woodland Creek, Dyer Creek, Mill Creek, Swantown Creek, Jacobs Creek, and Herring Branch. On the 1612 John Smith map of the area, it was called the Tockwogh River.

The Elk River is a tidal tributary of the Chesapeake Bay on the Eastern Shore of Maryland and on the northern edge of the Delmarva Peninsula. It is about 15 miles (24 km) long. As the most northeastern extension of the Chesapeake Bay estuary, it has served as one entrance to the Chesapeake & Delaware Canal since the 19th century. The canal and river now serve as one boundary of the Elk Neck Peninsula. The river flows through Cecil County, Maryland, with its watershed extending into New Castle County, Delaware and Chester County, Pennsylvania. Elkton, the county seat of Cecil County, is located at its head. Its total watershed area is 143 square miles (370 km2) (including the Bohemia River), with 21 square miles (54 km2) of open water, so its watershed is 15% open water. It is south and east of the North East River, and north of the Sassafras River.

The Havre de Grace Racetrack was an American horse racing track on Post Road in Havre de Grace, Harford County, Maryland. Nicknamed "The Graw," it operated from August 24, 1912, to 1950. For a time, it was owned by the Harford Agricultural and Breeders Association and also by the notorious gambler Arnold Rothstein. The Havre de Grace Handicap was one of the important races in the American northeast for many years. Its winners include U.S. Racing Hall of Fame inductees Roamer, Crusader, Seabiscuit, Sun Beau, Equipoise, and Challedon. Some Hall of Fame horses lost this race. In the 1919 running, Cudgel beat two Hall of Famers: Exterminator and Triple Crown champion Sir Barton. On September 29, 1920, Man o' War won the Potomac Handicap at Havre de Grace. His son, U.S. Triple Crown winner War Admiral, won his first race here on April 25, 1936. The track was located halfway between the cities of Philadelphia and Washington, D.C. In the 1940s, it began losing customers to Delaware Park Racetrack and Garden State Park Racetrack in New Jersey. By 1949, its owners were forced to turn over some of their allotted racing days to Baltimore's Pimlico Race Course. In January 1951, the Havre de Grace Racetrack was sold to Alfred G. Vanderbilt II, owner of Pimlico Race Course, and Morris Schapiro of Laurel Park Racecourse. who closed the facility and transferred the track's racing allotment dates to their own tracks. The Havre de Grace Racetrack is now the property of the Maryland National Guard, which uses the former clubhouse as offices. The grandstand, minus the canopy, has been converted into a warehouse. Nothing of the actual track remains, but an aerial view reveals a curved line of trees along the final turn.

Martha Lewis is a Chesapeake Bay skipjack built in 1955. Her home port is Havre de Grace, Harford County, Maryland.She was listed on the National Register of Historic Places in 2008. She is assigned Maryland dredge number 8.

A statue of Ernest Burke is a statue of Havre de Grace, Maryland-born baseball player Ernest Burke (1924–2004). It was created by sculptor Austen Brantley and was erected in Havre de Grace's Millard Tydings Memorial Park in 2021.