By Michael Delos Reyes

Are you planning to put a fence around your property but you are not certain where the start and end of your property is? If that is the case, better let your Geodetic Engineer install mohons over your property first.

A mohon, in layman’s terms, is a cylindrical concrete marker that is used as the standard marker to delineate a property boundary. These markers are also used as reference points for subsequent surveying projects. Other markers known as Geodetic Monuments have established coordinates or positions where surveyors can refer the exact locations of another property’s boundaries. Surveyors then mark the positions of the boundaries using a mohon/survey monument.

What does a mohon look like?

Based on Executive Order No. 192 dated June 10, 1987, and DENR Administrative Order No. 2007-29 (DAO 07-29) dated July 31, 2007, the following shall be the dimension for Geodetic Monuments:

Table 1. Dimensions of Geodetic Monuments as per DAO 07-29.

For Geodetic Monuments, they should be fabricated with a reinforced steel bar (10 mm in diameter for vertical bars and 8 mm in diameter for ties) and satisfying the requirements of class A concrete specifications in the ratio of 1:2:4 such as 1 cubic meter of cement, 2 cubic meters of sand, and 4 cubic meters of gravel.

Image1. Graphic representation on the properties of a Geodetic Monument.

It shall be marked on top with engraved letters which consist of 5 parts namely Provincial Code, Control Point Number, Year Established, Order of Accuracy, and the office or entity that established the Reference Monument.

Image 2. An example of a Geodetic Monument which can be found in Digos City, Davao Del Sur  (Source: Photo retrieved from:

For Standard Lot Corner which you can see in your surveyed properties:

Image 3. Graphic representation on the properties of a mohon used in private surveys  
Image 4. A mohon placed in a surveyed lot.

There are a number of marks that can be seen on top of a mohon. The most common is PS. “PS” stands for Private Survey/Surveyor; it is common in properties surveyed by Geodetic Engineers owned/claimed by its clients. To name more of the marks, we also have PSP which are private surveys done to properties owned/claimed by a Province, BL or Bureau of Lands are Government executed surveys, and  PLS or Public Land Subdivision are Government executed subdivision surveys.

Other Possible Markings

There are instances that the boundary can not be established with the standard monuments due to concrete walls, buildings, trees etc. According to the manual, the following are allowed as a substitute boundary mark:

  1. Concrete posts which are part of the fence that are not less than 10cm in diameter or metal pipes with no less than 2cm in outside diameter.
  2. Edible fruit trees or trees belonging to the first group as per forestry classification with no less than 15cm in diameter.
  3. Concrete walls.
  4. Fixed or immovable hard rocks with an exposed surface of more than one meter in diameter.
  5. Peg, being of a composition that will resist destruction by fire, natural corrosion, or decay with a nominal dimension of 50 millimeters square in cross-section for at least 100 millimeters from the top and not less than 400 millimeters in length.
Image 5. Steel Rod, an acceptable corner mark (photo retrieved from:

Interference or Disturbance of Mohon

Interference or disturbance of mohon is considered a crime and is punishable by law. Under Article 313 of the Revised Penal Code on altering boundaries or landmarks, “Any person who shall alter the boundary marks or monuments of towns, provinces, or estates, or any other marks intended to designate the boundaries of the same, shall be punished by arresto menor or a fine not exceeding Twenty thousand pesos (P20,000), or both.”

If you are planning to verify or if you are in doubt that your property’s boundaries or mohon were altered or disturbed, you can reach Lira Perin Habana, founder of LPH Land Surveying Services. She has been a licensed GE since 2014. She is a registered member of the Geodetic Engineers of the Philippines – NCR Chapter (GEP-NCR) and has been consistently providing reliable service to their clients since 2016.

***Information and figures were taken on The Manual on Land Survey Procedures retrieved from: (visited Sept 24, 2021).

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