Zoning Near NAS Patuxent River, St. Mary's County: AICUZ, APZs, and Noise Contours

What AICUZ is, and why it reaches beyond the base boundary

The Air Installation Compatible Use Zones (AICUZ) program is a Department of Defense framework, adopted at NAS Patuxent River in 1978, designed to keep land uses near an active military airfield compatible with aircraft noise and accident risk -- rather than letting incompatible development (dense housing, schools, hospitals) creep into the highest-risk flight paths over time. The program works by mapping two related but distinct things around the airfield: Accident Potential Zones (APZs), which reflect the statistical concentration of aviation mishaps along runway approach and departure corridors, and noise contours, measured in day-night average sound level, reflecting how loud aircraft operations are on the ground at a given distance and flight frequency.

At NAS Patuxent River specifically, current joint St. Mary's County Commissioners/Navy meeting materials describe an APZ Zone II noise contour of roughly 65 decibels that extends into parts of the county well beyond the installation's own boundary -- meaning a private parcel that looks, on a map, to be a comfortable distance from the runway can still sit inside a mapped AICUZ zone. NAS Patuxent River also conducts recurring, scheduled noise-generating testing -- Southern Maryland news reporting documented a 16-day noise advisory in September 2026 for Field Carrier Landing Practice events, illustrating that this isn't a historical or theoretical concern but an ongoing, operational reality for nearby residents.

An active, coordinated program: the county and the Navy meet regularly on encroachment

What distinguishes St. Mary's County's situation from many other Maryland counties with a nearby military installation is how actively the two governments coordinate on this issue specifically. St. Mary's County Commissioners and the Commanding Officer of NAS Patuxent River hold regular joint meetings dedicated to base encroachment issues, including updates on accident potential zones, clear zones, and high-noise areas. Recent meeting materials describe discussion of a proposed AICUZ disclosure statement that would be provided to residential leases in affected areas -- a formal mechanism specifically intended to make sure a renter (and, by extension, prospective land buyers evaluating similar areas) understands the AICUZ status of a specific property before committing to it.

That coordination produced a genuinely major, very recent update: NAS Patuxent River released an entirely new AICUZ study on August 13, 2026, following a public open house on August 4, 2026, replacing the installation's previous study, which dated to 2009. The new study incorporates current aircraft types, flight-test activity, and mission requirements at both Patuxent River and its Webster Outlying Field auxiliary airfield -- and one of its most notable changes was adding a new Accident Potential Zone reaching into part of Drum Point, in neighboring Calvert County, illustrating concretely that these mapped zones can expand into new areas as the base's mission evolves, not just shrink or stay fixed. If you're evaluating land anywhere near the installation, ask specifically whether the parcel's zone status reflects this 2026 study rather than the older, now-superseded 2009 version.

For a land buyer, this active coordination cuts in your favor in one specific way: because the county and the base treat this as an ongoing, current planning issue rather than a settled historical fact, both sides maintain updated information you can actually request. It also means AICUZ zone boundaries and noise contours are not necessarily static -- changes in flight operations, aircraft types tested at the base, or a periodic AICUZ study update can shift the mapped areas over time, so a zone designation confirmed even a few years ago should be reconfirmed before you rely on it for a current purchase decision.

What to check before buying land near NAS Patuxent River

Three concrete steps: (1) ask St. Mary's County's Department of Land Use and Growth Management directly whether a specific parcel falls inside a mapped AICUZ zone, an Accident Potential Zone, or a specific noise-contour band, since these designations can affect what the county will permit to be built there even where county zoning alone would otherwise allow it; (2) if buying with residential intent, ask specifically about the proposed (or, by the time you're reading this, possibly finalized) AICUZ disclosure requirement for leases and whether an equivalent disclosure practice applies to a sale, since this is an evolving, actively discussed county policy area; and (3) if a parcel is close enough to the installation that noise is a practical day-to-day concern rather than a legal technicality, ask about the base's current testing and flight-operation schedule, since NAS Patuxent River is a flight-test center with genuinely variable, sometimes intense noise-generating activity rather than a fixed, predictable commercial-airport pattern.

It's also worth understanding what an AICUZ designation does not do: it is a land-use compatibility guideline the county can incorporate into its own zoning and permitting decisions, not a federal taking of private property rights or a guarantee of compensation. A property inside an APZ or high-noise contour remains privately owned and, depending on the county's specific zoning response, may still be buildable -- but density, use type, and disclosure obligations can be more restrictive than an otherwise-identical parcel further from the installation. Confirm directly with the county rather than assuming either that AICUZ status makes a parcel unbuildable or that it has no practical effect at all.