Sixth Principal Meridian

The Sixth Principal Meridian is the single most widely used reference line in the entire Public Land Survey System. Established in 1855, it serves as the north-south baseline for surveys across five states: Colorado, Kansas, Nebraska, Wyoming, and South Dakota. If you work with legal land descriptions anywhere in the central Great Plains or the northern Rockies, you encounter Sixth Principal Meridian PLSS references regularly.

Initial Point and Baseline

The Sixth Principal Meridian originates at an initial point located at approximately 40°00' North latitude and 97°22' West longitude, in north-central Kansas near the Nebraska border. From this point, the meridian line runs due north and south, while the associated baseline extends east and west. Together, these two lines form the grid from which all townships, ranges, and sections in the five covered states are measured.

Surveyor General John Calhoun oversaw the establishment of the initial point. By the mid-1850s, settlement pressure was pushing westward across the Kansas and Nebraska territories, and the federal government needed a survey framework to support the Homestead Act and the disposition of public lands. Field crews fanned out from the initial point to begin subdividing millions of acres.

States Covered by the Sixth Principal Meridian

Kansas

Kansas is entirely surveyed under the Sixth Principal Meridian. Every legal land description in the state references this meridian, from the eastern farmland along the Missouri River to the short-grass prairie of the High Plains. Oil and gas activity in south-central Kansas, wheat farming across the central corridor, and ranching operations in the Flint Hills all rely on PLSS descriptions tied to the 6th PM. Use the Kansas PLSS converter to convert any Kansas description to coordinates.

Nebraska

Nebraska falls entirely within the Sixth Principal Meridian survey. The state's agricultural economy — one of the largest in the country — depends on precise land descriptions for crop insurance filings, USDA FSA program enrollment, and irrigation district management. The Nebraska PLSS converter handles all Nebraska descriptions.

Colorado

Colorado's eastern plains are surveyed under the Sixth Principal Meridian, while the mountain and western portions fall under other meridians (the New Mexico Principal Meridian and the Ute Meridian). Oil and gas operations in the Denver-Julesburg Basin, agricultural parcels on the eastern plains, and rural property transactions across the Front Range corridor all reference the 6th PM. Check the Colorado PLSS converter for Colorado descriptions, or read the full Colorado PLSS guide for details on which meridian applies where.

Wyoming

Most of Wyoming is surveyed from the Sixth Principal Meridian. The state's mineral extraction industry — including coal, oil, natural gas, and trona mining — generates thousands of legal land descriptions annually. Drilling permits filed with the Wyoming Oil and Gas Conservation Commission require exact PLSS locations, and a transposed range or township number can delay an Application for Permit to Drill. Convert Wyoming descriptions with the Wyoming PLSS converter.

South Dakota

South Dakota uses the Sixth Principal Meridian for most of the state, with the exception of the Black Hills region, which is surveyed from the Black Hills Meridian. Agricultural operations, tribal land management, and hunting lease descriptions across the central and eastern parts of the state all reference the 6th PM.

Format Examples

Legal land descriptions referencing the Sixth Principal Meridian typically follow this pattern:

• 14-5N-3W 6th PM — Section 14, Township 5 North, Range 3 West (section-level, 640 acres)
• SENE 22-3S-68W 6th PM — Southeast Quarter of the Northeast Quarter, Section 22, Township 3 South, Range 68 West, Colorado (a 40-acre tract)
• NESW 25-5N-30E 6th PM — Northeast Quarter of the Southwest Quarter, Section 25, Township 5 North, Range 30 East (a 40-acre tract)

The "6th PM" suffix distinguishes these descriptions from parcels measured under other principal meridians. In states like Colorado, where more than one meridian applies, including the meridian reference is essential to avoid ambiguity.

How to Convert a Sixth Principal Meridian Description

1. Go to the PLSS converter on Township America.
2. Enter your legal description in the search field — for example, SENE 22-3S-68W 6th PM.
3. Township America returns the latitude and longitude for the parcel center and boundary coordinates.
4. For multiple descriptions, use the batch converter to process hundreds of 6th PM descriptions at once by uploading a CSV.
5. Developers can integrate Sixth Principal Meridian lookups directly into their applications through the PLSS API.

Why the Meridian Reference Matters

The Sixth Principal Meridian covers more land area than any other single principal meridian in the PLSS. Anyone working with rural land records, mineral rights, agricultural programs, or public land management across these five states encounters it daily. Understanding which meridian governs a particular parcel is the first step in correctly interpreting and converting a PLSS description to coordinates.

A common error is omitting the meridian reference when converting coordinates. Two parcels with the same township, range, and section numbers but different principal meridians can be hundreds of miles apart. In Colorado, a description referencing "T3S R68W" could fall under the Sixth Principal Meridian (eastern plains) or the New Mexico Principal Meridian (mountain region). Always confirm the governing meridian before converting.

Historical Context

The Sixth Principal Meridian was one of the later meridians established in the PLSS. By 1855, earlier meridians (the First through Fifth) had already organized surveys across Ohio, Indiana, Illinois, and other eastern public-land states. The rapid westward expansion following the Kansas-Nebraska Act of 1854 created urgent demand for a new meridian to anchor surveys across the central territories.

Field surveys extended from the initial point over the following decades, eventually reaching the Rocky Mountains in Colorado and the northern plains of Wyoming and South Dakota. The resulting grid remains the legal framework for land ownership in all five states to this day.

Frequently Asked Questions

What states does the Sixth Principal Meridian cover?

The Sixth Principal Meridian governs PLSS surveys in five states: Kansas, Nebraska, Colorado (eastern plains), Wyoming, and South Dakota (most of the state except the Black Hills region). It is the most widely used principal meridian in the US survey system.

How do I identify the Sixth Principal Meridian in a legal description?

Look for a meridian suffix such as "6th PM," "Sixth Principal Meridian," or "6th P.M." at the end of the legal description. If you are working with land in Kansas or Nebraska, the Sixth Principal Meridian always applies. In Colorado, Wyoming, or South Dakota, the meridian depends on the specific location within the state — always verify which meridian is referenced before converting.

What is the difference between the Sixth Principal Meridian and other principal meridians?

Each of the 37 principal meridians in the PLSS serves as a reference line for surveys in specific states or regions. The Sixth Principal Meridian covers the central Great Plains and northern Rockies, while others — such as the New Mexico Principal Meridian or the Black Hills Meridian — cover adjacent areas. The meridian determines the origin point for all township and range numbering in its coverage area.

Can I convert Sixth Principal Meridian descriptions in bulk?

Yes. The Township America batch converter processes CSV files containing hundreds or thousands of 6th PM descriptions at once. Upload your file and get coordinates back for every entry. For automated workflows, the PLSS API supports programmatic lookups at scale.