Survey Numbers Explained: How Rural Land Subdivision Works in Tamil Nadu

| Blog

Last updated: Oct 8, 2026

What is a Survey Number in Land Records?

A survey number (also called S.No. or Survey No.) is a unique identifier assigned to a specific parcel of land by the government during an official land survey. Every distinct parcel of land within a revenue village receives its own survey number when revenue officials systematically survey and map the area. A survey number is unique only within a revenue village, not across a taluk, district, state, or country. The same survey number, say Survey No. 45, can and does exist in hundreds of different revenue villages across the state. To uniquely identify a piece of land at a broader administrative level, the survey number must always be combined with its village name (“Ur”), taluk, district, and state. For example, the complete unique reference would be: Survey No. 45/2A, Karungulam Village, Srivaikuntam Taluk, Thoothukudi District, Tamil Nadu. This full hierarchy is what makes a land parcel truly unique across the country.

Purpose of a Survey Number

• Identifies a land parcel within its revenue village
• Forms the basis for all legal and revenue records: patta, chitta, adangal, etc.
• Used in sale deeds, court documents, loan agreements, and government records
• Helps locate land on revenue maps (Tippan / FMB: Field Measurement Book)

How a Survey Number Gets Subdivided Over Time

When part of a survey number changes hands, for example through the sale of a portion, a family partition, a court decree or a government acquisition, the survey number can be sub-divided. This happens only when the sub-division is applied for or ordered and the survey staff carry it out. Until then the land stays under the parent number, often with several names on one joint patta. Each sub-division creates a new number derived from the parent. Sub-division does not delete the original survey number; it stays as the root of every sub-division made from it.

What Each Survey Number Means, Step by Step

Survey Number with Subdivision Example: Survey No. 45, Karungulam Village, Srivaikuntam Taluk, Thoothukudi District, Tamil Nadu

These numbers show how a sub-division number can develop. They are an illustration, not a formula. Notation varies according to the survey record, so always copy the number exactly as shown in your current Patta, A-Register or FMB.

Key Rules for Subdivision

• Sub-division keeps the original survey number as the parent identifier
• The total land area never changes during subdivision, it only gets divided. For example, if Survey No. 45 was originally 2 acres, and it is split into 45/1 and 45/2, those two pieces should together still add up to 2 acres in the records. If 45/1 is further split into 45/1A and 45/1B, those two must together equal 45/1’s area. On paper, no land is created or lost; it is only shared differently. If a fresh measurement on the ground shows a different extent, the records may need correcting by the survey staff
• Each recorded sub-division is separately identified in the survey and revenue records, with its own extent and boundary details reflected in the FMB/FMS. It is also shown against the relevant patta holding. One patta can cover several survey numbers or sub-divisions belonging to the same holder, and a sub-division can also remain under a joint patta with several names
• Multiple splits are most common in old family properties divided across generations
• Registering a sale or partition at the Sub-Registrar Office does not by itself create the new sub-division number. That comes through a patta transfer with sub-division, decided at the Taluk office after survey work; our Patta Transfer guide explains the steps

Survey Number Format Reference

As a survey number is subdivided over time, its notation usually follows a pattern. Here is what each part of the number means:

• The first number (e.g. 45) is the original survey number assigned during the government’s first land survey of that village. Sub-division does not change it, however many times the land is split. It can change in other ways: a town survey gives land in a surveyed town a new Town Survey Number, and a resurvey can renumber land. Older deeds may therefore carry an old number that has to be matched to the current one.
• The number after the slash (e.g. 45/1, 45/2) is the first-level subdivision number, assigned the first time the original parcel is split. The first piece becomes /1, the second /2, and so on. On the Tamil Nadu government portal (eservices.tn.gov.in), this is entered as the Sub-Division Number field separately from the survey number.
• The letter after the sub-number (e.g. 45/1A, 45/1B) is assigned when a sub-divided piece is split again. Letters A, B, C are commonly used at this level. Real records on the TN e-Services portal show sub-division numbers written as “2A” or “1B”.
• Deeper subdivisions continue with further letters and numbers, for example 45/1A1 or 45/1A1B. However, in practice, most land records in Tamil Nadu remain at the first or second subdivision level (e.g. 45/1 or 45/1A). Subdivisions beyond two levels are uncommon, and notation at those deeper levels varies by taluk and by the survey record, so always copy the number exactly as shown in your current Patta, A-Register or FMB.

Note: Land in towns covered by the Town Survey uses Town Survey Numbers instead. See our guide to Town Survey Numbers and the TSLR.

Frequently Asked Questions

Is a survey number unique across the whole state or country?

No. A survey number is unique only within its revenue village. The same number, e.g. Survey No. 45, can exist in hundreds of different villages. It only becomes a fully unique reference when combined with the village, taluk, and district.

Does the original survey number change when land is subdivided?

Not because of a sub-division. Sub-division keeps the original number as the root and records each part as a new number derived from it. The number itself can change in other cases, for example when a town survey or a resurvey renumbers the land, so match any old number in older deeds to the current one.

How many times can a survey number be subdivided?

There’s no fixed legal limit, but in practice most Tamil Nadu land records stay at the first or second subdivision level. Deeper subdivisions exist, mainly in old family properties divided many times, and notation beyond the second level varies by taluk.

Does subdividing a survey number change the total land area?

No. In the records, the areas of the sub-divided pieces should add up to the area of the original parcel. Sub-division changes how the land is recorded and shared, not how much land exists. If a fresh survey finds that the ground does not match the recorded extent, that is a separate correction handled by the survey staff.