Blog · September 30, 2026
What Is an Instrument Number?
An instrument number is the recorder’s identifier for one filed document, such as a deed, an easement, or a plat. Cite it with the county. It locates the paper. It does not locate the corners by itself.
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One document, one identifier
Recorders speak of instruments: the deed is an instrument, the easement is an instrument, the plat is an instrument. The instrument number is the office’s key to that filing. It may be a year plus a sequence, a pure sequence, or a number that includes a document-type code. A plat citation might read Instrument No. 2016-004512 of the county records. Take that to the recorder’s index, not to the assessor’s parcel search, unless the parcel page happens to store the same citation. Lot 12 is not an instrument number. Section 12 is not an instrument number. The temptation is to type every integer you see into one search box. Write a label beside each integer before you search.
How plats get cited inside deeds
A deed of a platted lot often says according to the plat recorded as Instrument No. such and such. That clause pulls the plat into the deed by reference. You have not finished reading the deed until you have the plat. The deed may be two pages and the plat six sheets. Easements work the same way. Subject to the easement recorded as Instrument No. 88421 is an empty phrase until you read 88421 and see the strip it describes. The strip might be a centerline with a width, a parcel with metes and bounds, or a blanket over the quarter. The number does not hint which. County GIS may draw an easement line it was given and may omit an instrument it was never given. Absence from the layer is not a release.
Copies and the stamp
The official copy is the one in the recorder’s file, with the stamp. A photocopy in a closing packet can be incomplete, missing a sheet of the plat. Check sheet counts against the title block, such as sheet 2 of 4. If you only have sheet 2, you do not have the plat. Platbookmapper will not hand you the instrument. It links to county GIS, which is the assessment map, not the recorder’s image. Do not invent an instrument number from a GIS attribute that looks numeric. And do not stake a line from the number alone. The number is an address in the filing system. The courses inside the document are the description.
What to do next
- Label the instrument number with county, type of document, and year if it is embedded.
- Open the document the number names before you rely on a subject-to clause.
- Confirm you have every sheet of a multi-sheet plat.
- Keep parcel ids and lot numbers in different fields.
The mix-up to avoid
Stopping at the deed’s lot number and never opening the instrument number of the plat. The lot number is a pointer. The plat is the map of the lot.
Questions people ask
What if the number has letters in it?
Keep the letters. A prefix can mark a document type or a year. Dropping a letter can retrieve a different series. Copy the stamp, hyphens included.
Does the instrument number tell me the land is validly subdivided?
It tells you a document was recorded. Approval, vacations, and later replats are other documents. Recording is a necessary part of the public record and not the whole land-use story.
Find the county map
Start at Platbookmapper, search the county, and open the local GIS link. Write down the parcel number before you compare the screen to a paper plat.
Not a survey. County GIS and tax parcel maps are assessment and planning layers. They are not a substitute for a recorded plat, deed, or licensed survey.