What is the arpent system and how does it relate to PLSS in Louisiana?

The arpent system is a French colonial survey method that divided land into long, narrow lots running back from river or bayou frontage. Arpent lots predate American annexation and were confirmed as valid private land claims. They appear most commonly along the Mississippi, Red River, Bayou Teche, and coastal bayous. Where arpent and PLSS descriptions meet in a title chain, both systems must be understood to complete the title research.

What are the Florida Parishes and why do they use the St. Helena Meridian?

The Florida Parishes are the southeastern Louisiana parishes east of the Mississippi River (including East Baton Rouge, East Feliciana, West Feliciana, St. Helena, Livingston, Tangipahoa, Washington, and St. Tammany) that were part of Spanish West Florida rather than the original Louisiana Purchase. They were acquired separately in 1810 and surveyed under the St. Helena Meridian, established in 1819.

Why are township numbers in Louisiana expressed as South?

Louisiana's PLSS baselines pass through the northern portions of the state, so nearly all Louisiana townships are south of the baseline. This is reflected in descriptions using S designations (1S, 2S, etc.). Unlike northern states where all townships are north of the baseline, Louisiana's geography places most of the state south of its controlling baselines.

Can I use this converter for Louisiana oil and gas leases?

Yes, for leases in parishes covered by the Louisiana or St. Helena Meridian PLSS. Enter the section, township, and range from the lease description to map the leased tract. For leases in south Louisiana parishes where arpent descriptions predominate, confirm that the lease includes a PLSS description before using the converter.

Louisiana PLSS Converter — Section Township Range to GPS

Convert Louisiana Public Land Survey System (PLSS) land descriptions to GPS coordinates using the Louisiana / St. Helena system.

Convert Louisiana Land Descriptions

Enter a Louisiana PLSS land description to get GPS coordinates instantly.

Example: NE 7 10S 5E Louisiana Meridian

Open the converter

Understanding Louisiana's PLSS System

Louisiana has one of the most complex land survey histories in the United States, and that complexity is written into every title search in the state. Louisiana is the only state in the continental US that was never fully converted to the rectangular survey system, and the result is a survey landscape where PLSS descriptions, French arpent long lots, Spanish colonial grants, and federal private land claims all coexist — sometimes within a single parish.

The Public Land Survey System in Louisiana operates under two principal meridians. The Louisiana Meridian, established in 1807, governs the western and central portions of the state. The St. Helena Meridian, established in 1819, covers southeastern Louisiana, including the Florida Parishes east of the Mississippi River that were acquired from Spain separately from the main Louisiana Purchase territory. Together, they cover the portions of Louisiana that were surveyed under the rectangular system — roughly the northern and western parishes and the Florida Parishes in the east.

The arpent system — Louisiana's other major survey framework — reflects the state's French colonial heritage. Arpent lots were long, narrow strips of land running back from a river, bayou, or road frontage, with the narrow end facing the water. A typical arpent lot might be three to five arpents wide and forty arpents deep. These lots were surveyed before American annexation and were confirmed as valid private land claims under federal law. They appear most frequently along the Mississippi River, the Red River, the Bayou Teche, and the coastal bayou country of south Louisiana. Where arpent and PLSS descriptions meet, title research can become extremely intricate, and accurate GPS conversion of whatever PLSS descriptions exist in the chain becomes particularly important as a fixed reference point.

Principal Meridians

Louisiana Meridian St. Helena Meridian

Common Use Cases in Louisiana

Who converts Louisiana PLSS descriptions — and why.

Oil and Gas Leasing in the Haynesville and Gulf Coast

Louisiana is a major oil and gas producing state, with the Haynesville Shale in the north and offshore Gulf Coast production in the south. Onshore lease descriptions in the northern and central parishes reference Louisiana Meridian PLSS descriptions. Converting these to GPS supports lease mapping, pooling order filings with the Louisiana Office of Conservation, and surface use agreement negotiations.

Agricultural Land in Northern Louisiana

The Red River valley and the upland parishes of northern Louisiana support cotton, soybean, and corn production on PLSS-surveyed farmland. Agricultural land sales, FSA program records, and conservation easements in these parishes all reference Louisiana Meridian PLSS descriptions that need GPS conversion for acreage verification and field mapping.

Timber and Forest Management

Louisiana's Kisatchie National Forest and the commercial timber lands of the central and northern parishes are managed using PLSS descriptions. Timber sale contracts, forestry management plans, and private timberland transactions reference Louisiana and St. Helena Meridian descriptions. GPS conversion supports field boundary identification and GIS analysis for forest managers.

Title Research in Mixed Survey Areas

South Louisiana title research frequently involves both PLSS and arpent descriptions in the same chain of title. Where a PLSS description exists, GPS conversion establishes a reliable spatial reference that can be used to locate arpent boundaries relative to the rectangular grid. This is especially useful in parishes along the lower Mississippi and in the coastal bayou country.

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How to Convert Louisiana Legal Descriptions

Three steps from legal description to GPS coordinates.

Identify the survey system and enter your description

Louisiana has both PLSS and arpent survey systems. For PLSS descriptions, type or paste your Louisiana or St. Helena Meridian description into the converter. A western Louisiana description reads: NE 7 10S 5E Louisiana Meridian. A Florida Parishes description reads: SW 14 3S 8E St. Helena Meridian. If you have an arpent lot description, consult a Louisiana title attorney before attempting conversion.

Verify the map result

The converter plots the PLSS parcel on an interactive map. Louisiana township numbers use South designations (1S, 2S, etc.) because the baseline passes through the northern part of the state. Toggle on aerial imagery to cross-check against known landmarks, roads, or water features.

Export for downstream work

Download coordinates as CSV, KML, or GeoJSON. Louisiana oil and gas landmen export to lease mapping platforms; title attorneys export to parish assessor GIS viewers; timber managers import into forest inventory software; agricultural users export to FSA portal tools.

Processing a Louisiana oil and gas lease inventory, a northern parish agricultural portfolio, or a timber management parcel list? Batch conversion handles any number of Louisiana or St. Helena Meridian descriptions from a single CSV upload.

Learn about batch conversion

Frequently Asked Questions

Common questions about Louisiana PLSS descriptions and conversion.

Louisiana uses two PLSS meridians: the Louisiana Meridian (western and central parishes) and the St. Helena Meridian (the Florida Parishes of southeastern Louisiana, east of the Mississippi River). Most PLSS-surveyed land in Louisiana references one of these two meridians.