Stone Structures of Northeastern United States Logo (c) 2008 Historic Structures Link Native American Structures Link Stone Quarrying Link

Stone Cairns

Stone cairns are found throughout North America from the sub-arctic regions of Canada to the lower 48 states. The highest concentrations of cairns are found on the eastern seaboard from the Chesapeake Bay north into the Canadian maritime provinces and westward to the Great Lakes region. Stone cairns are also known as rock piles, stone mounds, and stone heaps. They come many different shapes, configurations, and sizes.

Table of Contents

I. Definitions
II. Field Clearing and Stone Wall Pile Identification
III. Combined Cairn & Field Clearing Pile Identification
IV. Property Boundary Stone Cairn Identification
V. Hiking Trail Cairns Identification
VI. Native American Ceremonial Cairn Identification

I. Definitions

Stone structure researchers make a distinction between a rock pile built for a specific purpose and a rock pile which is a byproduct of agricultural activities like field clearing or stone wall building. Researchers are generally in complete agreement with each other about the need to make this distinction, but, to date they have not agreed upon what terminolgy to use.  This website uses the following terminolgy:

CAIRN: A cairn is an intentionally constructed pile of stones. It is built one stone at a time. Cairns have been used by humans in the northeastern United States as far back in time as 5,000 years ago and continue to be used today. Cairns were built by both Native American Indians and white settlers. They were used by the Native Americans for ceremonial purposes and by white settlers for utilitarian purposes.

STONE PILE: A stone pile is a disorganized heap of stones created as the result of field clearing or for the purpose of stone wall building. A stone pile was never intended to be an intentionally built stone structure with a specific purpose. Rather it is the byproduct farming related activities.

II. Field Clearing and Stone Wall Pile Identification

Field Clearing Stone Piles were used to get rid of unwanted stone. Stone was dumped out of a cart, wagon or stone boat. It was loosely piled with stone scatter around the edges. They are found at the edge of fields and occasionally on a wooded island in middle of field. Stone size is mixed.

Stone Wall Building Piles are found as a series of stone piles in a straight line along the intended line of a wall. The piles can be a mix of different size stones or piles of sorted sized stones. Some of these lines of piles have a wall started and in progress. Others were piled up with the intention of building a wall that never got started. The piles are dumped and therefore exhibit stone scatter around the edges. The piles are all the same size as the same wagon or cart was used to create each pile. They are usually spaced evenly apart along the line.

III. Combined Cairn & Field Clearing Pile Identification

In some cases, field clearing stone was added to an existing Native American cairn. The combined field clearing pile and Native American stone cairn can be identified by the compactness of the cairn (generally with small to medium sized stones) to which was added field clearing stone dumped from a wagon or rolled off of stone sleds. The field clearing stone will be out of character with the cairn. In many cases the field clearing stone will be boulder size and found around the edges of cairn or occasionally on top of it. With smaller size field clearing stone the typical stone scatter is generally evident. This practice of adding field clearing stone to existing cairns is well documented at the Miner Farm in Hopkinton, RI (Bob Miner, personal communication, 2006)

IV. Property Boundary Stone Cairn Identification

Property Boundary Marker Cairns are single small piles of stone. They often times but not always have a metal post. They can sometimes by identified by modern surveying marks like orange paint or surveyor’s tape.

V. Hiking Trail Cairns Identification

Trail Cairns are placed at regular intervals along a path. Cairns are uniform in style and size. They were common years ago, and today they are still used above tree line on some mountains such as Mt. Washington. They were built by hikers and Boy Scouts in the 19th and 20th centuries.

Field Clearing Stone Piles

Fig. 1 - Field clearing stone pile

Stone Wall Building Stone Piles

Fig. 2 - Stone wall building piles

Combine cairn and field clearing stone pile

Fig. 3 - Stone cairn with field clearing boulders added to it.

Property Boundary Stone Cairn

Fig. 4 - Cairn with metal pipe in middle

Hiking Trail Cairn

Fig. 5 - Hiking trail cairn Haystack Mountain, NH

VI. Native American Ceremonial Cairn Identification

Native American cairns are generally found in groups. The cairns within the group show a random, irregular placement. They generally contain several different styles and sizes. Many groups (but not all) are found within a walled-in field. Some stone walls are Native American and others were built by farmers. A group of cairns enclosed by stone walls is sometimes referred to as a “cairn field.”

Base of Cairn

The use of base identification is the primary means of classifying cairns. Classifying cairns aids in tracking cairn traits within a local area, a regional area, and between one region and another region. Identification of bases is divided into three groups: ground, base stone, split stone. Every known cairn falls into one of these three groups.


Ground refers to any cairn built directly on the ground. Cairns on the ground have a wide range of size from the small two feet diameter by few inches high to sixty (+) feet diameter by five (+) feet high.

Ground cairns come in several different designs. The mound design with a rounded dome top is the most common. It comes in small up to extra large. Large cairns have varied construction. They range from mounds to straight-side vertical walled cairns. Depressions are occasionally seen in large cairns. Some cairns are attached to corners of stone walls. Others were built on hillsides. A few hillside cairns cover the whole hillside. These usually have a retaining wall. Other hillside cairns were built to create platforms on side of hill. Seasonal streambeds in some regions are a favored place to build a cairn.

Large cairns of the mound or hillside design have two distinct ways of being created. First is to add a single stone at a time. Second is to add a whole small mound cairn on top of the cairn already built. Some of these extra-large cairns appear to have a mix of both single stone addition and whole small cairn addition. Small whole cairns are most easily seen along edge of large cairn where the shape can be seen.

Mounded Ground Cairn

Fig. 6 - Large mounded ground cairn

Corner Wall cairn

Fig. 9 - Triangule shaped cairn build into the corner of two stone walls

Vertical Wall Ground Cairn

Fig. 7 - Walled ground cairn

Depression in Cairn

Fig. 10 - Close-up of a depression in a cairn

Hillside Cairn

Fig. 8 - Hillside cairn with retaining wall

Layered Cairn

Fig. 11 - Cairn made from layers of flat stones

Base Stone

The base stone can be an above ground boulder, below ground boulder with exposed top, above ground bedrock called an outcrop, or surface level exposed bedrock. Base stone ranges from ground level up to three to four feet high. Height is sometimes a factor but not always. It is a site by site evaluation. Stones with splits filled with other stones are a separate category, see Split Stone.

Cairns built on base stone range from a single stone to a few stones to large quantities of stones. The stones can be placed on top of the base stone, attached to one or more sides of the base stone, on top & attached, or placed on top and trailing to ground. The cairn can be a single layer of stones, haver vertical walls retaining smaller stones, be solidly built of interlocking stones, a mound of stones, etc.

Cairn - Mound of stones on top of boulder

Fig. 12 - Mound of stone on base stone

Cairn - Single stone in a notch

Fig. 15 - Single stone in notch of base stone

Vertically walled cairn on bedrock

Fig. 13 - Walled cairn with interior stone fill on base stone

Cairn - Two stones on top of boulder

Fig. 16 - Two stone on base stone with quartz vein

Single layer of stones on base stone

Fig. 14 - Single layer of stones on base stone

Cairn - Single layer of five stones on top of boulder

Fig. 17 - Five stones on base stone

Split Stone

Split stone exhibits a total split or crack in the base stone. Splits are found in single boulders completely split into two sections facing each other, outcrops with one or more splits, and boulders with cracks. The split stone is always above ground or has one face exposed as in some outcrops. Split-stone boulders range from 1’ high to 6’ high.

Split stones at cairn sites are found with and without stone fill. A split stone without fill that has a cairn nearby is a spirit portal to the Underworld. It is rare. The split stones with fill are split stone cairns. Fill can partially fill the split or completely fill the split. Occasionally extra stones will be found on top of boulder or outcrop in addition to the filled splits. As a general rule there is one or two split boulder cairns per site, however, there are always exceptions.

Split boulder with no stone fill
Split Boulder Cairn

Fig. 18 - Split boulder without stone fill

Cairn - Split Outcrop

Fig. 19 - Two splits filled with stones


An annotated bibliography with quotations of pertinent passages concerning Native American usage of stone cairns is available on the Source Materials-Cairns webpage.

Copyright (c) 2005-2007, James E. Gage & Mary E. Gage. All Rights Reserved.