Spotted Lanternfly inSt. Mary's County, MDSPOTTED LANTERNFLY GUIDE
St. Mary's County is Maryland's southernmost county on the Western Shore — confirmed for SLF in 2022 as populations pushed into the tip of the Southern Maryland peninsula. The county's defining landmark is Naval Air Station Patuxent River, one of the nation's premier naval aviation research and testing facilities, whose large restricted-access grounds create a unique SLF monitoring and management challenge: Tree of Heaven can establish unchecked on military property, creating a potential SLF reservoir adjacent to civilian agricultural landscapes. Point Lookout State Park at the confluence of the Potomac River and Chesapeake Bay marks Maryland's southernmost point and a priority ecological monitoring zone. Leonardtown, the county seat, and the Route 5 and Route 235 corridors are primary SLF spread pathways through this rural and semi-rural county.
Maryland is under a statewide spotted lanternfly quarantine as of March 2026. Moving regulated articles out of Maryland requires inspection.
Highest activity zones
SLF Hotspots in St. Mary's County, MD
Naval Air Station Patuxent River (NAS Pax River)
Active zone
Point Lookout State Park
Active zone
Potomac River confluence area
Active zone
Leonardtown historic district
Active zone
Route 235 / Route 5 corridors
Active zone
Primary SLF food source
Tree of Heaven in St. Mary's County, MD
Tree of Heaven is present along St. Mary's County road corridors, Potomac River waterfront margins, and the Route 5 and Route 235 agricultural edges — providing SLF dispersal pathways from the established Charles County and Calvert County populations southward into Maryland's southernmost county. NAS Patuxent River's perimeter fence lines and adjacent civilian road margins are a priority concern where restricted-access military grounds can harbor Ailanthus populations that are difficult to manage. Point Lookout State Park road margins and Leonardtown historic district edges are additional monitoring zones as SLF continues to advance to the very tip of the Southern Maryland peninsula.
Identify Tree of Heaven →Local action resources
What To Do in St. Mary's County, MD
Report a Sighting
Every sighting in St. Mary's County, MD maps the invasion front. Report directly to Maryland Department of Agriculture.
Report Now →Squish on Sight
See a spotted lanternfly? Kill it immediately — it is legal and encouraged in all states. Learn the best kill methods.
Full Fight Guide →Map ToH in Your Block
Tree of Heaven removal cuts off SLF food supply. Add ToH sightings to the community map to guide removal efforts.
View Sighting Map →Statewide resources
Full MD State Guide
County-level data, quarantine zones, treatment guides, and agency resources for the entire state.
See the full MD guide →Community intelligence
Live Sighting Map
See where SLF has been spotted near you in St. Mary's County, MD. Add your own sighting to help map the front.
Open the Map →Free weekly fight briefing
Fight SLF in St. Mary's County, MD.
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