States Bordering Maryland: Four Neighbors Plus D.C.

Maryland's compact shape (12,407 mi²) touches four states and the District of Columbia:

• Pennsylvania — North (Mason-Dixon Line, surveyed 1763–67)
• Delaware — East (Transpeninsular Line + arc boundary)
• West Virginia — West (Potomac River north branch, Fairfax Stone)
• Virginia — South/West (Potomac River main stem, Smith Point)
• District of Columbia — Carved from Maryland (1790), borders NW (Western Ave, Eastern Ave)

Water Boundaries Matter

The Potomac River belongs to Maryland to the low-water mark on the Virginia shore (1632 charter, confirmed 2003 SCOTUS). This gives MD control of bridge/tunnel rights and riverbed resources.

Chesapeake Bay

Maryland's eastern shore fronts the Bay; Virginia shares the main stem. The Bay Bridge (US-50) connects Annapolis to Kent Island.