Jacksonville's Atlantic Coast: Which Beaches Are Eroding and What Protects Them

Jacksonville's Atlantic coast is made up of ocean beaches, dunes and inlet shorelines with salt marsh behind them, and the National Park Service says the Timucuan Preserve is home to some of the last remaining unspoiled coastal wetlands on the east coast (NPS).

The state erosion inventory follows the Duval shoreline from the Big Talbot Island side of Nassau Sound past Little Talbot Island to Fort George Inlet (Florida DEP), where the state places the Huguenot Memorial Park bird area (FWC). The federal sand project covers the 10 miles from the St. Johns River south jetty to the Duval and St. Johns County line (USACE and BOEM assessment). The City of Jacksonville's Kathryn Abbey Hanna Park has 1.5 miles of sandy beach (City of Jacksonville).

Behind the beaches lies the marsh. Salt marsh makes up about 75% of the Timucuan Ecological and Historic Preserve, roughly 35,000 acres (NPS). In the high marsh, smooth cordgrass and black needlerush grow side by side in a patchy mosaic. The park service credits the marsh with protecting shorelines from erosion, filtering runoff, absorbing floodwater and buffering storm waves, and notes that estuaries shelter and feed over 75% of marine fisheries species.

Last verified: October 18, 2026, against the June 2026 DEP erosion inventory, the BOEM and Corps borrow area assessment, NOAA Mayport gauge records and the FWC and City pages for Huguenot Memorial Park.

The state lists 10.4 miles of Duval County beach and 0.7 mile of inlet shoreline as critically eroded, plus 2.0 miles of eroding but non-critical inlet shoreline on Nassau Sound (DEP Critically Eroded Beaches, June 2026).

For the Duval list, the Department of Environmental Protection defines critically eroded shoreline as a segment where erosion of the beach or dune system threatens or has caused the loss of upland development, recreational interests, wildlife habitat or important cultural resources (DEP). Under sections 161.101 and 161.161, Florida Statutes, the department was directed in 1986 to identify those beaches and keep a long term plan for their restoration.

The 10.1 miles south of the river keep their designation even though sand has been placed there, because DEP retains the label on restored beaches so they stay eligible for state funding for long term management and monitoring (DEP). The report says roughly half of all designated critically eroded beaches in Florida are currently managed.

One detail to watch: the Duval County entry in the June 2026 report still says its most recent revisions were made in January 2000, while the same entry says the county is reviewed annually (DEP). The report points readers to the DEP Critically Eroded Beaches webpage for the most current list.

Sand comes back through the federal Duval County Shore Protection Project, which periodically renourishes 10 miles of Atlantic shoreline from the St. Johns River south jetty to the St. Johns County line, with the City of Jacksonville as local sponsor (USACE and BOEM).

The Duval project traces to Section 301 of the Rivers and Harbors Act of 1964, Public Law 89-298, according to the Bureau of Ocean Energy Management's finding of no significant impact (BOEM). The Corps authorization table dates construction and periodic renourishment to October 27, 1965 and extended federal participation in renourishment through 2040 to November 19, 1986. The Corps first weighed alternatives to beach nourishment in a 1974 environmental impact statement.

For the Duval Shoal S borrow area, the assessment describes about 1.4 million cubic yards of beach compatible fill dredged from about 8 miles east of the beach and placed in a 135 foot wide berm at +11.0 feet mean lower low water (USACE assessment). Because that borrow area lies more than 3 nautical miles offshore on the Outer Continental Shelf, BOEM had to authorize use of the sand through a negotiated agreement. Sediment samples taken there in 2013 showed fine to medium grained quartz sand with about 7 percent shell, and the assessment estimates potential sand in the wider Duval Ridge Field on the order of 10 billion cubic yards.

The assessment states the purpose plainly: the project is needed to reduce shoreline erosion and protect valuable property along the Duval County coastline (BOEM). The Corps Jacksonville District constructs the project, and the City of Jacksonville is its local sponsor.

Seabirds nest at Huguenot Memorial Park, where the Florida Fish and Wildlife Conservation Commission's 82 acre Fort George Inlet Critical Wildlife Area is closed from May 1 to August 31 (FWC).

At Fort George Inlet, FWC lists the focal species as royal terns, black skimmers, laughing gulls, gull-billed terns, sandwich terns, brown pelicans and American oystercatchers, and says the site supports one of the largest nesting colonies of royal terns, laughing gulls and brown pelicans in the state (FWC). The dunes are posted closed during nesting, and because chicks often run across the open beach, park staff may post areas outside the official boundary.

The City of Jacksonville, which runs the park at 10980 Heckscher Drive, calls the colony one of the largest seabird colonies on the east coast and says beach driving is allowed along most of the seaward shoreline subject to seasonal nesting closures (City of Jacksonville). The city page states that the north end of the peninsula closes to vehicles seasonally for nesting shorebirds protected by the Migratory Bird Treaty Act, and it posted a closure notice dated June 11, 2025. The city describes the season as before Memorial Day and after Labor Day while FWC gives May 1 to August 31, so a driver should check the park office at (904) 255-4255 before heading for the north end.

Erosion reaches this park from the river side as well: the city reports that the main roadway was compromised by erosion along the St. Johns River, electrical lines had to be moved and a temporary road was built so the park could open (City of Jacksonville).

NOAA's tide gauge at Mayport shows a relative sea level trend of 1.15 inches per decade, from monthly means recorded between May 1928 and December 2025 (NOAA CO-OPS sea level trends).

For Mayport, NOAA lists a trend error of 0.05 inches per decade and notes that the record combines data from an earlier station, 8720220, from May 15, 1928 to November 15, 2000 (NOAA CO-OPS). For comparison, the same NOAA dataset gives the Fernandina Beach gauge a trend of 0.91 inches per decade.

The present Mayport gauge sits at the Bar Pilots Dock and was established on August 1, 1995 (NOAA station 8720218). Its highest recorded water level is 3.41 feet above mean higher high water, on November 10, 2022. The station page also posts the day's predicted high and low tides.

Building near Jacksonville's beaches falls under state coastal rules, chiefly Florida DEP's Coastal Construction Control Line program for structures and activities that can cause beach erosion or destabilize dunes (DEP CCCL Program).

The Duval County sand project itself works under DEP Joint Coastal Permit 0228528-001-JC, with the City of Jacksonville holding a DEP consistency concurrence dated April 18, 2005 (USACE assessment).

For any Duval County beachfront owner, DEP says the statewide program also guards against damage to upland properties and interference with public access, and that CCCL permits protect sea turtles and dune plants (DEP). Adopting a control line sets an area of jurisdiction where special siting and design criteria apply, and those standards may be stricter than in the rest of the coastal building zone because of the greater storm forces expected in the more seaward beach zone. The program takes questions at 850-245-8570, and its page links a Map Direct viewer for locating the line.

Sea turtles tie the two programs together. The Corps assessment for the Duval sand project notes that the coastal waters of Duval County mainly provide migratory and reproductive habitat for sea turtles, and that hopper dredges can harm swimming turtles (USACE assessment), while the state control line permits are written to protect sea turtles and dune plants (DEP).