How To Read A Plat Book
Plat Books are an excellent source to obtain section and quarter-section information needed to process your locate request.  These sources give tier, range and section information and are available for every county in the state of Illinois.  Quarter sections are easy to determine using the section boundaries. 

How can I determine what the section number is?  
Each section number is clearly marked on the township page in the center of each section (see illustration below). 

What are tier and range numbers? 
These numbers represent Township and Range and are indicated at the top of each Township page (see illustration below). 

How do I read my plat book?
The illustration below is a simplified example of how to read a plat book.  In addition, each county plat book contains detailed instructions regarding this procedure. 

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