GIS Legal Descriptions & Parcel Numbering

Township and Range Lines

Township and range lines divide land into 36 square mile areas (six miles x six miles). Township lines run east-west parallel to baselines every six miles. They are designated as Township 1N, etc., or Township 1S, etc. Range lines run north and south parallel to meridians. They are designated as Range 1W, etc., or Range 1E, etc.

Townships are created by the intersection of township and range lines. Each township is six miles square and divided into 36 sections. Townships are about 49.5 feet shorter at the top (north) than at the bottom (south) as these lines converge as they continue toward the North Pole.

The sections within a township are numbered consecutively from the northeast corner (Section 1), following a back-and-forth course until the last section in the southeast corner is numbered (Section 36). The one-mile-square areas typically contain 640 acres. They are the smallest subdivisions that were actually surveyed on all four sides. Compass directions are used to locate parcels in sections. The directions are abbreviated “N”, “S”, “E”, and “W”. Sections are usually divided into half and quarter sections: N1/2, NW1/4, etc.

Irregular townships were corrected along the northerly and westerly line of townships. Where these corrections occurred, government lots were established. These lots contain more or less than 40 acres and were assigned numbers, i.e., Lot 4 Section 16 instead of NW1/4NW1/4. Lot numbers were also used when ground barriers prevented the establishment of complete 40-acre tracts. This occurred where streams, lakes, or cliffs were involved in a survey.

Metes and Bounds: Metes are measures of length and bounds are boundaries. Metes and bounds are used when it is necessary or desirable to describe a parcel with irregular boundaries which does not conform to the rectangular system. The point of beginning and boundaries are identified in relationship to a monument, i.e., recognized marker, such as a section quarter corner, bridge, pile of stones, or natural features, such as a lake, stream, tree, etc.

For example: A tract of land in the northwest one-quarter (NW1/4) of the northwest one-quarter (NW1/4) of Section 30, Township 1 south, Range 60, west of the 6th P.M., described as follows: commencing from the northwest corner of said Section 30, thence south 20 degrees 30′ east 140.60 feet to the point of beginning; thence north 88 degrees 55′ east 200.00 feet; thence south 125.00 feet; thence south 88 degrees 55′ west 200.00 feet; thence north 125.00 feet to the point of beginning.

Recorded Plat

A parcel of land may be subdivided into blocks and lots by recording an approved map, called a plat, with the County Clerk and Recorder. A subdivision is a parcel of land divided into lots and blocks with proposed streets, alleys, public utility easements, and other information included by the subdivider. A plat is an accurate drawing showing dimensions and bearings sufficient to locate the subdivision as a whole or any part of it, such as lots, streets, alleys, and easements. A reader can look at a good plat map and clearly see north and know the location of a lot and its size. North is at the top of a map unless the north arrow states otherwise.

Requirements: Dedication, Acknowledgment, Map and Surveyor’s Certificate, Plat Approval and Acceptance and Recording.

• Dedication is a way to transfer streets and alleys to a city or county. The dedication should contain: a) The name or names of the owners and any mortgagees; b) A legal description of the property being subdivided; c) A dedication of the streets, alleys, and easements; d) The name of the subdivision.
• Acknowledgment (signatures notarized). The plat must be executed by the subdividers and mortgagees in the same manner as a deed is executed.
• Map and Surveyor’s Certificate. The surveyor must sign the plat, affix his seal, and certify that he surveyed the property and the plat represents an accurate drawing of the surveyed land.
• Plat Approval and Acceptance. The final plat of a subdivision must be approved by the proper authorities before it can be filed and recorded. Dedicated roads, streets, or alleys must be accepted by the proper officials before they can become the property of the county or city. If not accepted, they remain the property of the subdivider and are taxable. Officials may refuse to accept dedication of roads, especially in mountain subdivisions, because roads may not meet specifications of the commissioners may not want the burden of road maintenance.
• Recording. A copy of the subdivision plat must be approved and recorded with the County Clerk and Recorder.

Descriptions of Lots and Blocks: After a plat has been filed, any lot, block or other parcel of land specified in the plat may be described by other numbers or names than those previously used. If there are two subdivisions in a county with the same name, they are distinguished by the recording date, file number, reception number, or other such designation which should be added to clarify identification. Areas previously subdivided may be changed by filing an amended plat or resubdivision plat. The changes might include relocation of lot lines, the alteration of streets or alleys, or the addition of streets. The latest recording data should follow the legal description to properly identify the parcel. For example:

Lot 8A, Block 5 Smith Subdivision, a resub of Lot 8 Block 5

Reading and Understanding Legal Descriptions

Typical legal description by government survey system:

North half (N1/2) of the northeast quarter (NE1/4) of Section 34, Township 4 north, Range 58 west of the 6th Principal Meridian.

The abbreviated version of this description is:

N1/2NE1/4 Sec.34 T.4 N. R.58 W.,6th P.M.

Commas have an important meaning in legal descriptions. When reading a legal description, the word “and” should be substituted for the comma.

Locating a Parcel

• Principal Meridian – The first step in locating a parcel is determining which principal meridian and baseline were used. In the example above, the parcel lies within the area surveyed using the 6th Principal Meridian and the Colorado Baseline.
• Range – The range will be indicated by a number east or west of the principal meridian. Reading the above description, note that the parcel lies in Range 58W. This indicates the parcel lies west of the 6th Principal Meridian in the 58th Range west.
• Township – The township will be indicated by a number north or south of the baseline. The legal description above indicates “Township 4 N.” This indicates the parcel lies north of the Colorado Baseline in the 4th Township North. The description “T. 4 N. R. 58 W.” designates the parcel lies in the township where the 58th Range west of the 6th Principal Meridian and in the 4th township north of the Colorado Baseline intersect.
• Section – Next, locate the section where the parcel lies. The parcel above is located in Section 34.
• Subdivision of Section – Determine which portion of the section is being described. The parcel described above lies in the north half of the northeast quarter.

Assessors have the authority to abbreviate any description. It will be legal if it correctly and effectively describes the parcel in a way that it can be easily located and not be confused with any other parcel.

39-5-103, C.R.S. states: “In listing tracts or parcels of real property, the Assessor shall identify the same by section, or part of a section, township, and range, and if such part of a section is not a legal subdivision, then by some other description sufficient to identify the same. In listing town or city lots, he shall describe the same by number of lot and block, or otherwise, in accordance with the system of numbering or describing used by the town or city in which said lots are located.”

Assessment Maps

Assessment maps are designed especially for the particular requirements of the Assessor’s Office. In a broad sense, any map used by the Assessor to inventory, locate, and identify property could be called an assessment map. Tax maps are at least 4,000 years old. The British Museum contains a series of clay tablets dating back to 2300 B.C. which are inscribed with land surveys which were used for taxation purposes.

By establishing and maintaining an efficient mapping system, real property can be inventoried to ensure all taxable parcels are assessed and that double assessments and omissions do not occur. An effective filing system results when all appraisal records, maps, and other records are indexed according to a parcel identification number. The permanent parcel identification number greatly simplifies the use of computerized assessment systems for sorting, computing, and distributing values and taxes. Preparing and maintaining complete, accurate assessment maps is required by 39-5-103 C.R.S. Map guidelines, established by the Property Tax Administrator, include: a) Map size; b) Map scale; c) Minimum information to be plotted, line weights and symbols to be used and drafting requirements and procedures; 4) Definition of basic mapping terms; 5) Development of a parcel system.

A parcel identification system is the tie between ownership, assessment maps, and tax roll entry. Identification systems reduce lengthy legal descriptions to unique numerical expressions which positively identify all properties in the County.