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GLO Historic Plat Map

Retrieval System

 
   

Public Land Survey Glossary
Base Line : An imaginary line extended east and west on a parallel of latitude and crossing a Principal Meridian at an Initial Point, used for surveyors in locating and describing land under the Public Land Survey System
Bearing : The compass direction of a survey line. 
Bearing Tree : A marked tree used to insure a corner could be found if the monument marking a corner was destroyed.  Surveyors marked the trees with prescribed marks, noting their species and size. 
Chain : A unit of measurement used by the surveyors.  Chains measured 66 feet long, with 80 chains equaling one mile.  Each chain was composed of 100 links of 7.92 inches each. 
Dependent Survey : A later survey dependent upon information gathered in the original survey.  To create a dependent survey, the surveyors return to the field. 
Extension Survey : A survey that adds to an existing survey.
Fifth Principal Meridian : The principal meridian governing surveys in all or parts of the following states: Arkansas, Iowa, Minnesota, Missouri, North Dakota and South Dakota.
Fourth Principal Meridian : The principal meridian governing surveys in all or parts of Illinois, Minnesota, and Wisconsin.
Fractional Section : A section which contains one or more subdivisions of less than forty acres due to irregular exterior boundaries, or the encroachment of water or other land which could not properly be surveyed.
Fractional Township : A township containing less than 36 normal sections, usually because of invasion by a segregated body of water, or by other land which cannot properly be surveyed as part of that township or by closing the public-land surveys on State.  Half ranges and half townships are fractional townships by definition.
Government Lot: A subdivision of a section, which is normally described by a lot number — for example, lot 5.  A government lot may be regular or irregular in shape and its acreage varies from that of regular section subdivisions.  Typically government lots are located along meandering bodies of water.
Independent Survey : The first government survey of lands.  The original survey, or a survey not dependent on the original.
Initial Point : A point defined by the intersection of a base line and principal meridian.  This point is used by surveyors in locating and describing land under the Public Land Survey System. 
Island Survey : A later survey of islands.  For the original surveys, islands were sometimes skipped and then surveyed later.  
Link : A unit of measurement used by the surveyors.  Each link was 7.92 inches long.  One hundred links made up a chain.  Each chain measured 66 feet long, with 80 chains equaling one mile.  
Meander Corner : A corner established at the intersection of a meander line and a township or section line. 
Meander Line : The borderline of a navigable river or lake, sometimes noted on the plats.   
Omitted Land Survey : The survey of areas of lands, which after investigation are known to have been omitted from the original survey through error or fraud.
Principal Meridian : An imaginary line running north and south and crossing a base line at an initial point, used by surveyors for reference in locating and describing land under the Public Land Survey System. 
Township : The largest subdivision of land in the Public Land Survey System, measuring six miles square.  Public Land Survey System Townships do not correspond to political townships.  Public Land Survey Townships are named by the township and range numbering system.  Each township has a township number, which indicates its north-south position of the base line, and a range number, which indicates its east-west position of the meridian.
Quarter Section : A subdivision of a section, measuring a half-mile square (160 acres).
Quarter-Quarter : A subdivision of a quarter section, measuring a quarter-mile square (40 acres).
Range : Public Land Survey Townships are named by the township and range numbering system.  The range number indicates east or west position from a longitudinal meridian.
Resurvey : A later survey that reestablishes points and boundaries of the original survey.  To create a resurvey, the surveyors went back to the field. 
Section: A subdivision of a Public Land Survey Township, measuring one mile square (640 acres).  Each township has 36 sections.  
Supplemental Plat: A supplemental plat may be created with or without fieldwork.  It is designed to show a revised subdivision of one or more sections without change in the section boundaries and without other modifications of the subsisting record.  
Variance : Magnetic north and true north do not coincide at the same geographic point.  They differ by a number of degrees.  The discrepancy between magnetic and true north also differs with location.  Variance is the amount, at some geographic point, by which the direction to magnetic north varied from the direction to true north. 
Witness Corner : A monumented survey point being used as a reference, usually located near a corner.  A witness corner is used when the corner is so situated as to render its monumentation impractical.