Blog · October 14, 2026 · Washington
Using the Prosser Plat Map
Lots in Prosser trace back to recorded plats filed with the county.
Main page: Benton County, WA GIS & Parcel Viewer (official map link, county facts and neighboring maps).
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When a deed near Kennewick says lot and block, you'll need the Prosser plat map to make sense of it. What this Prosser guide covers: where plats are filed, how a plat differs from a parcel map, and what to look for on the sheet.
Who keeps the Prosser plat map
For land around Benton City, the deed or parcel record often names the subdivision and plat reference; bring that to the recorder's office or its online index.
Opening the official parcel viewer
Go first to the Benton County parcel viewer; it includes each tax parcel from West Richland to Kennewick. On ground around West Richland, type a street address, an owner's name or a parcel number, then pick the result to center the map on it. Closer to Richland, write down the parcel ID from that panel; each office in the county will want it.
A quick look at the area
Prosser holds the county offices, where most land records are kept. Other places on the map include Benton City, West Richland, Kennewick, and Richland, where town lots give way to larger tracts. About 215,219 people live in Benton County (Census estimate, 2023) on about 1,700 square miles. Benton County dates to 1905, and some chains of title near Richland are long. Landmarks such as Hanford Reach National Monument are easy to spot when you zoom out from Richland.
City limits and county records
Prosser lies within Benton County, Washington, so its parcels are on the county's map. Prosser is also the county seat, so deeds and plats are filed in town. Around Richland, the municipality handles matters such as zoning, permits and utilities for lots inside the boundary, but the county runs assessment and recording. Acreage past the city limits toward Benton City generally answers to county rules rather than the town's.
Amended plats
Lots near Kennewick can be combined or reconfigured by a replat, so check for later filings; vacated streets or alleys also get recorded.
Field tips
Most viewers work in a phone browser, which helps when you're standing on land near Kennewick, though signal can drop in rural spots. A saved image of the lot near Kennewick and its lines is a good backup.
Two different maps
Where lines don't match in Prosser, go with the plat and a surveyor's work.
Details on the Prosser plat map
Utility or drainage strips on a lot in Prosser can block a shed or pool; check the plat notes and any covenants.
Getting answers from the right desk
Anything recorded against property around Richland sit in the index kept by the County Auditor, sometimes only in person. Questions about what you can build around West Richland are for the local planning and health departments, depending on whether the land is inside town limits.
Sections, lots and bearings
Washington is laid out under the Public Land Survey System, so rural legal descriptions near Richland cite section, township and range. Each section is nominally a mile square, about 640 acres, with 36 sections to a township, though corrections make some sections near West Richland odd-sized. Write down the legal description for the tract near West Richland before you request a deed or survey.
What the map can't tell you
Acreage on the record is an assessed number; just a licensed surveyor can set the real boundary on land around Benton City. Out toward West Richland, records update in batches, so a deed recorded last month might lag behind.
Next door to Benton County
Benton County meets Morrow County, OR, Umatilla County, OR, Franklin County, Grant County, and Klickitat County; every one of them runs a separate parcel map. A tract near the line by Kennewick can be split across two assessors' files, so open the adjacent map before you assume the acreage. If you're looking near Kennewick, our state page links every bordering county map across Washington.
Where the recorded documents are
The map is an index, not the title: deeds, plats and easements for land near Benton City sit with the County Auditor. Out toward Kennewick, have ready the book and page from the tax record and the lookup takes minutes.
Requesting the plat
For a tract near West Richland, some counties put plat images online, while others require a visit or a request; copy fees are usually small.
When there's no plat
Acreage around Benton City outside a subdivision is often described by metes and bounds or survey description; the deed and any recorded survey describe it instead.
Questions about the Prosser plat map
What is a replat for land near Richland?
Good question; combining or splitting lots near West Richland usually needs a recorded plat change, often with a surveyor's drawing.
What does lot 7, block 3 mean near Richland?
Around Richland, lot and block refer to a numbered lot within a block on a recorded subdivision plat, so pull that plat for dimensions.
How do I get a copy of a plat in Prosser?
The County Auditor keeps recorded plats; small copy fees are common.
Where are historic plats for the town near West Richland?
For property near Kennewick, it varies; some offices have scanned older plats and some haven't; call before you visit.
What's the tax parcel number used for around Benton City?
It's the number the County Assessor uses to track a tract near Richland; copy it before you call anyone.
Open the official Benton County, WA parcel map See it in the Platbookmapper directory
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, especially for fences, setbacks, or boundary disputes.