Physical Geology Interactive: The Lab - Maps (Activities-Activity 4)

Activity 4: Tier and Range

In most of the United States,

tier and range is a common method

used for locating position

and is part of the U.S.

Public Land Survey introduced

in the 1785.

It is used in all states

except the original 13 and

Maine, Vermont, West

Virginia, Kentucky, and Tennessee.

Texas is also not part of this

system because it was

originally surveyed using the

Spanish land grant system.

The tier and range system

was designed primarily

for locating property lines and land description

on legal documents.

It is more

commonly used to locate parcels of land,

although it can be used

to locate a point.

Numerous principal meridians and baselines

have been established for the

middle and western parts

of the United States and

are used for determining location over

different sized areas (Fig. 1).

Selected north-south lines, principal meridians, and east-west lines, baselines (Fig. 1),

define the tier and range system.

Although the tier and range

system was supposed to be

completely rectangular,

some townships and sections are

irregular in shape because of

problems with the original surveys.

Range lines are parallel to the

principal meridian on 6-mile intervals.

The strips of land between

these lines are ranges and are numbered consecutively north and south

of the principal meridian.

At right angles to the range

lines and also at 6-mile intervals

from the baseline are tier lines.

These lines define strips of land,

tiers, parallel to the baseline. The intersection of a tier and

a range creates a square of land,

a township, 6 miles on a side.

Specifying the tier

(T3N) and range (R2E) that

intersect identifies a township.

A township covers an area

of 36 mi².

Fig. 1: Baselines (dotted blue lines) and principal meridians (solid red lines) of the United States.

Townships are subdivided into a series of 1-mi² sections, each covering 640 acres. They are numbered starting at one in the upper right corner of the township (Fig. 2). To provide a more precise location, sections are quartered and each quarter section identified by the quadrant it occupies. Quartering a section identifies a location within a square (a quarter section) a half a mile on each side. If greater spatial accuracy is required, quarters can be further quartered to produce eighth sections—i.e., squares a quarter mile on a side. Listing the subdivisions starting with the smallest, sixteenth, eighth, quarter, and working out to the range and tier specifies a point’s location. For example, the location of the parcel of land denoted by the shaded portion of section 27 in Fig. 2 is NE1/4, SW1/4, Sec 27, T3N, R3E. A point can be located by specifying the quadrant the point is centered in.

Fig. 2: Numbering of sections in a township.

To complete Activity 4, select one of the following files: