THE ST. TAMMANY PARISH LAND BRIEF
Land in the
Gulf Coast Flatwoods setting.
St. Tammany Parish has 845.3 square miles of land in Louisiana. 7 mapped landscape regions meet across St. Tammany Parish: Gulf Coast Flatwoods, Deltaic Coastal Marshes and Barrier Islands, Southern Pine Plains and Hills, among others.
Low plains mingle with barrier islands, lagoons, marshes and inland lake districts. Coastal and inland settings vary substantially within this warm southeastern landscape.
Regional context: Southern Coastal Plain ↗ · Regional mapping across the county footprint
Where the landscape changes
St. Tammany Parish intersects 7 mapped regional units. The largest mapped shares are:
- Gulf Coast Flatwoods41.3%
- Deltaic Coastal Marshes and Barrier Islands25%
- Southern Pine Plains and Hills18.5%
- Floodplains and Low Terraces10.8%
- Gulf Barrier Islands and Coastal Marshes2.5%
Mississippi Alluvial Plain in St. Tammany Parish
The Mississippi's broad alluvial plain includes river terraces, swales and natural levees. Small changes in elevation distinguish local settings within this generally flat river landscape.
Read the regional source ↗Southeastern Plains in St. Tammany Parish
Irregular plains of sand, silt and clay support a mix of pine and hardwood landscapes. The region has more relief than the lower coastal plain, with generally gentle stream gradients.
Read the regional source ↗Finding your parcel within St. Tammany Parish
The atlas lists 11 cities, towns, townships, and Census communities associated with St. Tammany Parish, including Lacombe, Slidell, Mandeville. The list includes overlapping geography types and does not divide the county into exclusive service areas.
St. Tammany Parish by land and water
The Census records 250.3 square miles of water within St. Tammany Parish, or 22.8% of its total area. That share is close to St. Tammany Parish’s 22.8%. This is geographic context; waterfront status and usable land must be checked at the parcel.
For scale, St. Tammany Parish has 183.2 times the land area of nearby Abita Springs town (4.61 square miles). These areas describe boundaries, not comparable property prices.
The Census boundary meets Jefferson Parish, Orleans Parish, St. Bernard Parish, St. John the Baptist Parish, Tangipahoa Parish, Washington Parish within Louisiana. A tract near one of these lines should be matched to the county identifier on its own records.

