Section Maps - cartographers & geographers in the house?

When I worked for a city, we had “section maps” that covered a certain standard area. This was in michigan. I really can’t tell you how big they were, etc. I’m hoping that some expert will recognize the phrase “section map” and tell me all about them.

Are sections standard for the whole us? Is “section map” the proper term, and is it specific to maps of this size area? Do “section maps” always contain a certain type of info? Tell me more.

Thank you,

js_my head is about to explode from acute frusteration_africanus

Mapping & blueprint scales are standard for Federal highways, & Army Corps of Engineers maps.

Otherwise, size, scale, & most other aspects vary widely from place to place. But the legend symbols areusually the same or similar enough to read at a glance.

“Section maps” would seem to be a local term.

Section maps come out of the Northwest Ordinance, probably the most important law passed under the Articles of Confederation. It set out a method for surveying and distributing the Northwest Territory (OH, MI, IN, IL, WI, mostly), which was later extended west, until it ran into the limits of rain agriculture somewhere around the 100th meridian.

Basically, off of standard meridians and baselines, townships (36 square miles) were surveyed, which were further divided into 1 square mile sections. These are then often divided into half, quarter and even smaller portions of the section, as needed and sold at auction, generally in quarter section portions.

So to answer your question, yes, all sections should be the same size, IF the area was platted under the Northwest Ordinance, barring quirks of local geography. They tried to continue this into the high plains, but where farmers couldn’t eke out a living on 160 acres, the system broke down. I think it may have picked up again on the west coast, but not sure about that…

The State of California is indeed platted by means of baselines and meridians; Los Angeles County is (entirely?) referenced by the San Bernardino Baseline and Meridian (SBBM).

Sections are parts of townships and are one mile square. Generally in rural areas of Michigan, your county roads are going to be on section lines. There being 36 sections to a township, that makes townships 6 miles square. In cities, the term loses its meaning. I’ve looked at local maps in Michigan for many years in my employment and have never seen the term section applied in Detroit, for example. I’ve never actually heard of a “section map”, but sections are easily seen on any county map.

We do have sections and townships across the entire state of Colorado (including the mountains). There are parts of Texas and California that did not get sectioned out. These areas are refered to Spanish land grants. Don’t know why they didn’t get sectioned out though.

Not sure why 160 acres would be an issue. That’s a quarter section. It would just be a matter of buying many quarters or a full section or whatever.

Washington (the state) is platted as well. I don’t remember much, but there are parcels of land set aside for various things, within each township. I know schools got a half section, which I believe is 144 acres. I can’t remember any more. 7th grade was 44 years ago.

Measuring America by Andro Linklater is an excellent, readable account of the history of surveying, concentrating on the USA.
It goes into fascinating detail about the early surveys of Colonial times right up to the present day.

Here’s an example of what we call “section maps” in Tulsa County:

As you can see, it’s really just an outline of real estate parcels in the county, and nothing more. It’s a handy reference tool for me, because if you know how the parcel numbering system works you can derive the complete parcel identification number from the map (very handy when dealing with parcels that don’t addresses).

As everyone else has stated, anything called a “section map” will in all likelihood refer to an approximately one square mile “section” under the Public Land Survey System. But exactly what sort of information would be on it would in almost certainly vary from one municipality/county to the next. But I would generally expect there to be some sort of outlines of real estate parcels or something to that effect, since the PLSS is, after all, a system for surveying real estate.

You ought to be able to get a section map of almost anywhere in the US. When I worked for the Forest Service, all our fire information was in Township & Range. It didn’t matter if you were in Minnesota, Arizona, Colorado, Oregeon, Nevada, Idaho, or whatever.

Does anybody know of an online source for these maps surveyed under this system? (Hopefully one that doesn’t charge for maps?)


The US Bureau of Land Management has interactive maps that show section, township and range data, which are downloadable as images or GIS shapefiles.

You’ll want a link I suppose :rolleyes: :smiley:

It’s called the Public Land Survey System, implemented in all states except on the east coast, Texas (we had our own screwy land-parceling methods…) and a few other exceptions.

Another possibility: USGS 7.5 minute series topographic maps also have Sections, Townships and Ranges shown right on the map, although sometimes it’s hard to make out exactly what the section number is if it’s in a crowded area (if you can’t make it out, what you need to know is that a township is six by six sections square, and Section 1 is located in the northeast corner, and the numbering “snakes” its way down with 36 being in the southeast corner).

You can access any USGS 7.5 minute series topos from

I KNOW the OP wasn’t asking about these, but for completness, 1:500,000 Aeronautical charts are called “sectionals” (at least in the US)
There are also Terminal Area charts (1:250,000) and (IIRC) Wide Area Charts (1:1,000,000).