Monday, May 16, 2016

The Cadastral Survey System Explained

My great grand uncle, Herbert Bartist Beck's farm land was spread across three different townships/ranges in Fergus County, Montana:
  • 20 North Range 24 East, abreviated as T20N R24E
  • T20N R25E
  • T19N R25E
Each township/range was six square miles in size:

The above diagram indicates the three township/ranges where Herbert Beck bought land. Each township/range was divided into 36 sections, which were 640 acres in size. As an example, we will use Township 20 North, Range 24 East (T20N R24E):

Herbert Beck owned land in four sections of T20N R25E. Sections could be further subdivided, typically into quarters, each comprising 160 acres. Then those quarters could also be quartered. Each quarter of a quarter section was 40 acres. So Herbert Beck's land was located in the following areas of Fergus County:

This system of legal land descriptions makes so much sense to me. It is so much easier than trying to find land my ancestors bought in Virginia, for example, 300 years ago when the description uses creeks, old trees and other landmarks which may no longer exist.

To learn how I use the cadastral survey to locate my ancestor's land today, click Working with Land Patents and Plat Maps.

All the diagrams included in this post were created using Microsoft Excel.


  1. I don't work with these surveys often, so when I do I have to go back and try to remember how it works. Thank you for your clear explanation and diagrams (as well as the link!)

    1. Thanks, Michelle. I truly love the Cadastral system but had to relearn it, like everytime, I encountered a homesteading ancestor. This is my new "cheat sheet!"