How Was Illinois’s Land Measured?
Surveying a state begins when an initial point is chosen. Then two lines, a baseline (east to west) and a principal meridian (north to sound) are created. These lines originate and intersect at the initial point. Next, Standard latitude lines are identified parallel to the baseline. All further surveying depends on this “lattice” of lines.
The land is then divided into survey townships of 36 square miles, 6 miles on each side. Township lines run parallel to the baseline (east-west), and range lines run north-south, each at six mile intervals. Townships are then subdivided into 36 sections of approximately one square mile (640 acres) and sections into four quarter-sections of 0.25 square mile (160 acres) each.
Defining uncharted wilderness by lines was a daunting task. Imagine hills, valleys, rivers, swamps, woods, etc. A typical location such as a heavily wooded area required surveyors to run a straight line through the woods from one fixed endpoint to the next. An axe man would clear a path through the trees and the underbrush while the flagman provided a sighting target for the surveyor. Once the straight line was cleared, two chainmen would measure and set a mark identifying the distance. The surveyor would then bring up the rear, sighting using a compass to make sure the crew stayed on course. A good surveying party could survey about 12 miles in one day.
After the township survey was finished, the chief surveyor made notes about the features of the land, how the land might be used, and the land’s general character (wooded, swampy, hilly, flat, etc.). This information would then be used in advertisements created by the land company to sell lots in the township.
Surveyed land was changed forever. A continuous stretch of wilderness from one geographic point to another had become a grid that could be identified and quantified. It had become a piece of property that could be titled and sold. Squatters and merchants were already rushing in ahead of the crowd, knowing that as soon as the land was opened for purchase it would be gobbled up in a very short time. Native Americans also knew they would soon have to leave their homes.
Surveyors’ Tools: Land surveying dates back to 1700 BC and the ancient Egyptians. By the 18th Century, a simple compass or circumferentor, a Gunter’s chain, and a set of plotting instruments were the basic professional equipment. Surveyors of Illinois also brought along a good supply of gunpowder, a rifle, a blanket, and other personal items. Notes were jotted in a field book, and on-site markers, such as piles of rocks or wooden stakes, were used to mark the corners of each property.
Photo: Wikipedia
Survey Measurement: Distances were measured in chains and links, based on Edmund Gunter’s 66 foot measuring chain. The chain–an actual metal chain–was made up of 100 links, each link 7.92 inches long.
There were 80 chains in one U.S. Survey Mile (differs from an International Mile by only a few millimeters). Two chainmen, one at each end, made the measurements. In forested areas, the lead chainman had to follow the correct bearing at all times, and keep the chain level, since all surveying distances are based on the horizontal distance, not the slope. In steep terrain, this meant either shortening the chain, or raising one end of the chain relative to the other, or both. In areas where measuring by chain was not possible, such as extremely steep terrain or that with water obstructions, distances were calculated by triangulation.
A groma was used to survey straight lines and right angles, thence squares or rectangles. They were stabilized on the high ground, and pointed in the direction it was going to be used. The helper would step back 100 steps and place a pole. The surveyor would tell him where to move the pole and the helper would set it down. Such simple tools have been used since Roman days.
A circumferentor consists of a circular brass box containing a magnetic needle, which moves freely over a brass circle, or compass. A pair of sights is located on the North-South axis of the compass. Circumferentors were typically mounted on tripods and rotated on ball-and-socket joints.
Survey Monumentation: Permanent on-the-ground objects were identified to mark exact locations of surveyed points and lines. These markers are legally binding, used for setting property lines. Both corner monuments as well as accessory objects that “witness” to them were used. Witness objects allow subsequent surveyors and landowners to find the original corner monument location should the actual monument itself be destroyed.
Sometimes squatters or homesteaders destroyed corner monuments if they felt their residence on the land was threatened. For this reason, destruction of corner monuments and/or witness objects was, and still is, a federal offense.
In the 19th century, corner monuments might be a rock pile, a wooden post, or a combination. Trees could be used if the corner happened to fall at the exact spot where one grew. Witnesses can be trees, rocks, or trenches dug in the ground; their exact locations relative to the corner, and the markings made on them, are also recorded in the surveyor’s official field notes.
On each witness tree (also termed bearing tree), two blazes were typically required, one chest height and one at ground level, in case the tree were illegally cut. The trees were inscribed with the township, range, and section information. Sometimes the trees were used to retrace a surveyed line or as proof that the line had been run correctly.
Currently The Witness Tree Project, a collaboration of the Morton Arboretum, The Field Museum, Notre Dame University, and other institutions, is attempting to locate any remaining witness trees in Illinois. For more about the project go to: http://chicagorti.org/WitnessTrees?fbclid=IwAR1pWVPJXYAwpOP3R7jxCQ4y3hmFBrpG8fpKF-DlWLCzE079ZcK9rj9R4C8
