Cypress Environment & Infrastructure is headquartered in Biloxi, and this page is our Mississippi reference for the full wetland sequence: field delineation, the U.S. Army Corps of Engineers (USACE) jurisdictional determination (JD), and the federal and state permits. It focuses on what differs here: four Corps districts, the role of the Mississippi Department of Marine Resources (MDMR) in the three coastal counties, and the Mobile District’s stream mitigation SOP.

Background topics have their own pages: how a wetland delineation works, approved and preliminary JDs, the Section 404 permit, and the broader list of environmental permits.

Which Corps District Reviews a Mississippi Site

Mississippi is divided among four Corps districts along watershed divides. From the USACE Regulatory Areas of Responsibility GIS data:

Mobile District (SAM): the Gulf Coast and Pascagoula River basin, including Jackson, Harrison, George, Stone, Greene, Perry, Forrest, Wayne, Jones, Jasper, Clarke, and Covington Counties and most of Hancock, Lamar, and Smith; and the Tombigbee basin of east and northeast Mississippi, including Lowndes, Clay, Monroe, Lee, Itawamba, Noxubee, Oktibbeha, and Lauderdale and most of Kemper, Chickasaw, and Newton.
Vicksburg District (MVK): the Delta, the Jackson metro area (Hinds, Madison, and Rankin), and the Yazoo, Big Black, Homochitto, and Pearl River basins. Because the Pearl River drainage belongs to Vicksburg, western Hancock County and most of Pearl River County are Vicksburg sites even though they are near the coast.
Memphis District (MVM): the Hatchie River drainage in Alcorn and Tippah Counties and parts of Benton and Prentiss, plus small areas of DeSoto, Tunica, and Coahoma.
Nashville District (LRN): the Tennessee River drainage in Tishomingo County.

Many counties straddle a divide, including Pearl River, Hancock, Lamar, Simpson, Jefferson Davis, Winston, Pontotoc, and Union. Confirm the parcel on the Mobile District or Vicksburg District jurisdiction map before filing. In Hancock, Harrison, and Jackson Counties, wetland applications are submitted through MDMR under agreements with both districts (see below).

Wetland Delineation in Mississippi

The standard is the 1987 Corps Manual as modified by the Atlantic and Gulf Coastal Plain Regional Supplement (Version 2.0, 2010). The Delta lies in the supplement’s Mississippi Alluvial Valley subregion (LRR O), most of the interior in the Inner Coastal Plain (LRR P), and the coastal counties in the Outer Coastal Plain (LRR T). Several soil and hydrology indicators are limited to one subregion.

Conditions that drive most boundary calls in Mississippi:

Wet pine savannas and pitcher plant bogs. The supplement describes Gulf coast pine savannas as fire-maintained flats with a diverse grass and sedge understory, often with pitcher plants (Sarracenia), where hydrology comes mainly from rainfall, high water tables, and shallow overland flow. Without fire, these sites close in with pine and shrubs. They can dry out completely in the late spring and summer dry season, and upland annuals rated FACU can dominate in dry periods, so soils and hydrology often carry more of the decision than the plant list.
Bedded pine plantations. Silvicultural bedding reshapes surface hydrology and soils. The supplement’s Chapter 5 procedures for lands used for agriculture and silviculture apply, and boundaries are drawn on what the site would show under normal circumstances.
Delta bottomlands and farmland. Bottomland hardwoods in the Mississippi Alluvial Valley can lack surface water for months, and some soil and hydrology indicators apply only in LRR O. Prior converted cropland is excluded from waters of the United States. An NRCS wetland determination made for USDA program eligibility answers a different question from a Corps JD, so ask the Corps how it will treat an existing NRCS determination.
Tidal marsh in the coastal counties. MDMR staff determine the ordinary high water mark (OHWM) for coastal wetlands regulation, and state law says that OHWM is not the same as mean high water. The Corps’ Section 10 limit in tidal waters is the mean high water line. The report should address each line the reviewing agencies need.

Our Delineation Process

Desktop review. NWI maps, aerial imagery, FEMA flood zones, soil surveys, and topographic data, plus the Corps district boundary and whether the site is in Hancock, Harrison, or Jackson County, so the permit path is known before fieldwork.
Field investigation. Paired upland and wetland sample points at each boundary document plants, soil profiles, and hydrology indicators on the regional data form.
GPS mapping and flagging. We flag the wetland boundary in the field and map it with high-accuracy GPS, giving the design team and the agencies one spatial reference.
Delineation report. Boundary maps, data forms, photographs, and field notes, formatted for the Mobile or Vicksburg District, with streams classified as ephemeral, intermittent, or perennial.
Corps coordination. On request, we file the report with the district for a JD or attach it to the permit application.

Jurisdictional Determinations in the Mobile and Vicksburg Districts

The JD decides which of the mapped features the Corps regulates. An approved JD (AJD) gives a binding answer, normally good for five years (RGL 05-02). A preliminary JD (PJD) assumes jurisdiction to move a permit forward and cannot take a feature out of federal review. The Mobile District uses separate request forms for the two. Turnaround is not published; PJDs generally come back much sooner. More on our JD page.

The rule in force. Mississippi is one of the states where the January 2023 rule is enjoined. Jurisdiction here is decided under the pre-2015 regulations as narrowed by Sackett v. EPA (2023), not under the 2023 rule or its September 2023 amendments (EPA status page). A wetland qualifies only where it abuts a relatively permanent jurisdictional water with a continuous surface connection, which the agencies’ March 2025 guidance reads narrowly. EPA and the Army proposed a new definition on November 20, 2025 and supplemented it on September 9, 2026; it is not final. Our Sackett page has the background.

In practice. Pine savanna wetlands and flatwood depressions separated from streams by upland are the features most likely to be found non-jurisdictional, and an AJD is often worth requesting where that finding would change the site plan. Tidal wetlands in the coastal counties remain under MDMR’s coastal wetlands program regardless of the federal answer. Inland Mississippi has no standalone state wetland-fill permit that substitutes for a Corps Section 404. MDEQ Section 401 water quality certification rides only with a federal permit; when the Corps issues a non-jurisdictional approved JD for a feature, there is no 404 authorization and no corresponding 401 certification for that wetland. Local floodplain and construction stormwater rules apply either way. See isolated wetlands.

Non-Jurisdictional Waters After Sackett

After Sackett v. EPA (2023), many Mississippi wetlands and streams that lack a continuous surface connection to a relatively permanent water are no longer waters of the United States. When the Corps issues a non-jurisdictional approved JD for those features, Corps Section 404 authorization ends for that wetland. MDEQ Section 401 water quality certification does not apply without a federal permit, and Mississippi does not currently operate a separate inland wetland-fill permit for state-only waters.

Proposed / not in effect. MDEQ is developing a future State Water Alteration Program (SWAP) that would address impacts to waters of the State, including some waters that are no longer WOTUS. As of October 2026, SWAP rules are not final: MDEQ did not finalize its January 2025 proposal; it issued an Advance Notice of Proposed Rulemaking with draft framework text in January 2026; the informal comment period on that notice closed October 5, 2026; and MDEQ has said it intends to propose a full set of SWAP rules later in 2026 (mdeq.ms.gov/wots). Until final rules take effect, do not treat draft SWAP materials as current permitting requirements. Cypress will update this page when MDEQ adopts final regulations.

A delineation and, where useful, an approved JD still matter for buyers, lenders, and site planning: they document which features remain under Corps review and which do not. Cypress maps the boundaries, coordinates with the Mobile or Vicksburg District as needed, and can document the non-jurisdictional path for due diligence. Call 228-596-1580.

Permits: Federal, State, and Coastal

Corps authorization

Small fills are usually authorized under a nationwide permit (NWP). The current NWPs were issued on January 8, 2026 (91 FR 768) and run from March 15, 2026 to March 15, 2031. According to the Mobile District’s February 13, 2026 public notice, the district added no regional conditions to the 2026 NWPs, MDEQ issued conditioned water quality certifications for all NWPs on December 5, 2025, and MDMR issued conditioned coastal zone consistency decisions for all NWPs on October 29, 2025. Those state conditions apply to NWP use in Mississippi. The Vicksburg District issued its own regional conditions, so read them for Vicksburg sites. Larger projects need an individual permit with public notice, and work in navigable waters also needs Section 10 authorization.

MDEQ Section 401 water quality certification

The Mississippi Department of Environmental Quality (MDEQ) is the statewide Section 401 certifying agency for Corps permits that involve a discharge to waters of the United States. Under the current federal rule (40 CFR 121.4), a pre-filing meeting request is due at least 30 days before the certification request unless MDEQ waives or shortens that period; EPA proposed revisions in January 2026, so check the rule in effect when you file. Certification conditions on turbidity, stormwater, and construction methods travel with the Corps permit.

MDMR coastal wetlands permit (Hancock, Harrison, Jackson)

Under the Coastal Wetlands Protection Act (Miss. Code Ann. § 49-27-1 et seq.), MDMR regulates dredging, filling, killing or materially damaging vegetation, and structures that affect the ebb and flow of the tide in coastal wetlands, defined as publicly owned lands subject to the tide below the ordinary high water mark, along with publicly owned accretions and water bottoms. MDMR also runs the Mississippi Coastal Program for the three coastal counties. Applications for wetland impacts there are filed with MDMR through its wetlands permitting portal or the Joint Application and Notification Form, and MDMR forwards them to the Corps and MDEQ. See our 401 and coastal permit overview.

Listed species

Three federally listed species overlap wetland and upland work in south Mississippi. The gopher tortoise is listed as threatened throughout Mississippi. The dusky gopher frog is endangered, with designated critical habitat in Forrest, Harrison, Jackson, and Perry Counties. The Mississippi sandhill crane, an endangered subspecies, depends on the wet pine savannas of Jackson County. A Corps permit brings ESA Section 7 consultation with the U.S. Fish and Wildlife Service into the schedule when these species or their habitat may be affected. Our gopher tortoise survey page covers survey scope.

Compensatory Mitigation, Including Streams

Mobile District, streams. Stream debits and credits are calculated with the district’s 2012 Compensatory Stream Mitigation Standard Operating Procedures and Guidelines (SAM-2011-317-MBM). The adverse impact worksheet scores stream type, priority area (primary, secondary, or tertiary), existing channel condition, impact duration, dominant impact, and a length-based scaling factor. Credits come from separate in-stream and riparian buffer worksheets. Final designs are expected to follow natural channel design based on a reference reach, and riparian buffer preservation can supply no more than 30 percent of a plan’s credits. The SOP was written for ephemeral, intermittent, and perennial streams; after Sackett, it applies only to the streams that remain jurisdictional.
Mobile District, wetlands. The district’s mitigation page posts its wetland tools, including the Wetland Rapid Assessment Procedure (WRAP), the Proximity Factor Method for mitigation outside the impact’s watershed, and performance standards for pine flats, bayhead drains, and bottomland hardwoods.
Vicksburg District. Vicksburg uses the Modified Charleston Method for stream mitigation rather than a stream SOP like Mobile’s. The district posts the 2010 Charleston Method guidelines, which include the stream credit worksheets. Confirm current practice at the pre-application meeting before you price stream mitigation.

Bank credit availability by service area is posted in RIBITS. Related pages: mitigation banking, how stream mitigation works, and buying credits or establishing your own bank.

Cypress in Mississippi

Our published Mississippi work includes the wetland delineation, stream assessments, and ecological function assessments for the 166-acre Little Biloxi River Mitigation Bank (pine savanna, stream, and bottomland hardwood credits). For CN (Canadian National), we completed a 200-mile linear corridor delineation from Mobile, Alabama to Jackson, Mississippi that crossed both states and both the Mobile and Vicksburg Districts, along with endangered species surveys, stream characterization, an environmental assessment, and permitting. In the Mobile District we also completed the delineations and bank documents for the Lower Devil’s Swamp and Texas Flat mitigation banks, the latter a bedded former pine plantation. Coastal work includes a marsh reference site assessment for MDEQ and an invasive species assessment of 26 sites in the Mississippi Coastal Preserves Program.

Frequently Asked Questions About Wetland Delineation in Mississippi

Is wetland delineation required before I apply for a permit in Mississippi?

If your project may place fill in wetlands or streams, the Corps needs mapped boundaries to evaluate the permit, whether it is reviewed by the Mobile or Vicksburg District. In the coastal counties, MDMR needs them for the coastal wetlands permit. A delineation submitted with the application, or a JD, provides that boundary.

How do I know if my property in Mississippi has wetlands?

Wetlands are not always obvious. Pine savannas, flatwood depressions, and Delta bottomlands can look dry for much of the year. Desktop maps such as NWI flag likely areas; the boundary itself comes from field data.

Who regulates wetlands in Mississippi?

The Corps regulates waters of the United States through the Mobile, Vicksburg, Memphis, or Nashville District, depending on the basin. MDEQ certifies Corps permits under Section 401. In Hancock, Harrison, and Jackson Counties, MDMR regulates tidal coastal wetlands and runs the coastal program. Listed species are handled with the U.S. Fish and Wildlife Service.

How long is a wetland delineation valid in Mississippi?

An AJD normally stays valid for five years (RGL 05-02) unless new information comes up. Delineation reports and PJDs carry no federal expiration date, but expect the district to ask for fresh data after site changes, a long gap, or a rule change. We refresh older reports for phased projects.

Does a non-jurisdictional finding end the permitting?

It ends Corps Section 404 review of that feature, and with it any MDEQ Section 401 certification tied to that federal permit. Mississippi does not currently require a separate inland wetland-fill permit for waters that are not WOTUS. In the coastal counties, tidal areas can still need an MDMR coastal wetlands permit, and local floodplain and construction stormwater requirements apply regardless of federal jurisdiction.

What types of wetlands are common in Mississippi?

Bottomland hardwoods and cypress-tupelo swamps along the Delta and major rivers, wet pine savannas and pitcher plant bogs in the southeast and coastal counties, flatwood depressions and bayhead drains across the coastal plain, and tidal marsh along the coast.

Request Wetland Delineation in Mississippi

Tell us where the parcel is, how large it is, and what you plan to build. We will lay out the district, the state reviews, and whether a delineation, a JD, or both make sense.

Call us at: 228-596-1580
Email: [email protected]

Headquarters: 772 Howard Avenue, Biloxi, MS. Other offices: 150 Government Street, Suite 950-1000, Mobile, AL, and 13 Palafox Place, Pensacola, FL. Monday–Friday, 9 a.m.–5 p.m.

Wetland Delineation, JDs and Permitting in Mississippi