Spotted Lanternfly inWashington County, MDSPOTTED LANTERNFLY GUIDE
Washington County is western Maryland's largest county and a critical SLF gateway to the mid-Atlantic interior — confirmed in 2022, it sits at the junction of I-70 and I-81, two of the most heavily traveled freight corridors in the eastern United States. Hagerstown, the county seat, is a transportation hub where enormous volumes of truck and rail freight create constant vehicle-mediated SLF reinforcement from the established Frederick County and Pennsylvania infestation zones to the east. The C&O Canal National Historical Park runs along the Potomac River through the county, providing a linear Ailanthus corridor connecting populations from the DC metro area westward into western Maryland. Antietam National Battlefield — one of the most visited Civil War sites in the nation — is a priority monitoring zone as SLF spreads through the county's historic agricultural and open-meadow landscapes. The county is under Maryland's statewide quarantine in effect since March 2026.
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 Washington County, MD
Hagerstown urban core
Active zone
I-70/I-81 major transport interchange
Active zone
C&O Canal National Historical Park
Active zone
Antietam National Battlefield
Active zone
Potomac River corridor
Active zone
Primary SLF food source
Tree of Heaven in Washington County, MD
Tree of Heaven is established along Washington County's I-70 and I-81 road margins, the C&O Canal towpath, and Potomac River riparian corridor, creating primary SLF dispersal pathways from the Frederick County infestation zone westward into the Hagerstown basin. The C&O Canal National Historical Park towpath has Ailanthus populations lining historic canal margins for miles, extending SLF habitat through one of the Mid-Atlantic's most iconic linear trail corridors. Antietam National Battlefield road margins and Hagerstown urban canopy are priority monitoring zones as SLF populations continue to advance through this historically and agriculturally significant western Maryland county.
Identify Tree of Heaven →Local action resources
What To Do in Washington County, MD
Report a Sighting
Every sighting in Washington 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 Washington County, MD. Add your own sighting to help map the front.
Open the Map →Free weekly fight briefing
Fight SLF in Washington County, MD.
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