Researching property history in Arizona, Part 4: Plat Maps

(This is Part 4 of a series written by Research Library team member Chris Seggerman. Read Part 1. Read Part 2. Read Part 3.)

What does a neighborhood look like before it exists? How do blank square-mile sections fill with ordered rows of streets and houses? How does a developer sell that plan to investors or request development rights from the city and county for that neighborhood? Before the first shovel broke ground to build your neighborhood, those who planned it used a plat map.

Plat maps are filed by book and page number at the Maricopa County Recorder’s Office. The originals eventually pass to the State Archives. You can view unofficial copies of the maps here*.

This website wants you to enter the book and page number. That information can be found on a deed. The Maricopa County Assessor’s office also has links to this information on their parcel viewer.

Plat map example
(Image credit: C. Seggerman photograph of the original map located at the Arizona State Archives)

Historic plat maps are also interesting from aesthetic perspective. They predate computer-aided drafting, and some are practically works of art. They provide direct clues how a neighborhood used to look. The plat map for the Capitol Addition—Book 1, page 62– shows Tract A set aside for the site of the State Capitol, and other details. It shows the Valley Street Railway Company’s route down Washington Street. It also shows that several streets have changed name: Bingham became Monroe, Franklin became Adams, and Johnstone became Jefferson. It also shows that lots surrounding the capitol are small and narrow—a detail visible in slightly later aerial photos of the area.

Plat map example
(Image credit: C. Seggerman photograph of the original map located at the Arizona State Archives)

Some neighborhoods are platted by corporations. Other early plats show groups or individuals who gave neighborhoods now forgotten names. Simm’s Addition, registered with the County Recorder by James T. Simms in 1893, sits between Central and Third Avenue, just south of Interstate 10. Two of its streets, Westmoreland and Portland have parks in the middle of their streets, but only Portland remains. Westmoreland is now occupied by the Japanese Friendship Garden and the Irish Cultural Center, near the park. Interested researchers could construct the layout of the many neighborhoods sacrificed to Interstate 10 using plat maps alone.

You can also find development details you might not have thought about. For example, the area around Scatter Wash, where I walked home from high school, is a drainage easement. I grew up in terror that Scatter Wash might eventually be developed instead of remaining full of trees, bike ramps, and winding footpaths. The plat map explains “…no structure of any kind be constructed or any vegetation be planted nor allowed to grow within the drainage easements which would impede the flow of water over, under, or through the easements. The City of Phoenix may, if it so desires, construct and/or maintain drainage facilities on or under the land in the easements.”

That did not stop the City of Phoenix from clearing some vegetation and slightly reshaping the wash in the late 1990s, but the plat map explains that area will probably always remain undeveloped.

*If the electronic copy of the plat map at the County Recorder’s website is difficult to read, you can see the early originals at the State Archives or at the Recorder’s office.


Researching property history in Arizona, Part 3: The Lost Cities of State Highway Department Maps

(This is Part 3 of a series written by Research Library team member Chris Seggerman. Read Part 1. Read Part 2.  Read Part 4.)

These days, we take for granted that the Valley of the Sun contains a megalopolis: Not just one city, but  many, each outgrowing their original boundaries to rub against and occasionally spar with one another. Instead of crossing an expanse of road, farm fields, and citrus groves, we move from city to city by crossing a street. Sometimes only a small “Welcome To!” sign marks the boundary. In 1937, there was still room between cities, before individual communities began to vanish, overwhelmed and annexed by their neighbors.  The collection of county road maps acts as a gateway to those places.

The collection covers all the counties in Arizona, but Maricopa itself took 10 sheets. Almost every sheet shows one or two locations long since gone, sometimes just a ranch but often an entire small community. Beardsley, which gave its name to the arterial street in north Phoenix—now practically swallowed by Loop 101—is on sheet 3. Originally, it was a railroad junction, but vanished when the railroads expanded.


Highway and transportation map
Maricopa County Arizona: General Highway and Transportation Map. 1937. Sheet 3 of 10. Prepared by the Arizona State Highway Department in cooperation with the U.S. Department of Agriculture, Bureau of Public Roads. Data obtained from state-wide highway planning survey.” Historic Arizona County Road Maps. Arizona Memory Project.


While each sheet has such areas scattered throughout, Sheet 10 shows enlargements of 15 communities from the County.  For those interested in genealogy, the US Census Department used these maps to plan enumeration districts in the less-populated parts of Maricopa county for the 1940 census.

Locating the communities is easy enough, because the map gives coordinates of township and range. Each community had its own history, with slight variations on a theme: For example, Marinette used to be where Sun City is now, and gives its name to the recreation center there.


“Maricopa County Arizona: General Highway and Transportation Map. 1937. Sheet 10 of 10. Prepared by the Arizona State Highway Department in cooperation with the U.S. Department of Agriculture, Bureau of Public Roads. Data obtained from state-wide highway planning survey.” Historic Arizona County Road Maps. Arizona Memory Project.


In 1939, Sonerata was distinct enough to catch Highway Department cartographers’ attention, but today it is just a neighborhood at the southwest corner of Warner and Gilbert roads, annexed by Gilbert about ten years ago. The name is slightly misleading: Google Maps and the Maricopa County Assessor calls the neighborhood “Sonora Town” today, but it was Sonoratown when Gilbert realtor C.H. Russell subdivided the area in May of 1920.

This map is almost a checklist for anyone researching urban growth in Maricopa County.  Guadalupe, Gila Bend, Sunnyslope, Litchfield Park and Peoria are all still fairly present, but the rest are census designated places or ghost towns.


Researching property history in Arizona, Part 2: Maricopa County Land Ownership Maps

(This is Part 2 of a series written by Research Library team member Chris Seggerman. Read Part 1. Read Part 3. Read Part 4.)

Phoenix sprawls: Practically from the Bradshaws to the Sierra Estrella and South Mountain, from the White Tanks to the McDowell Mountains, urban growth has covered the valley in subdivisions and houses, crisscrossing the land with names. Population growth means more homeowners, and more homeowners mean more names to plow through if you are researching from present to past.

But what if you could go back before the sprawl, before phone books full of names, and start at the beginning, skipping back 113 years?  The Maricopa County Land Ownership maps on the Arizona Memory Project cover who owned what from 1903-1929.

Land ownership map

The originals are held at the State Archives, and can be viewed in person.

Each sheet covers a 36-section township. Earlier years have fewer maps, and the collection’s coverage grew as properties expanded. They act as good visual guides when you need to see who owned the northeast quarter of the southwest quarter of a section. Physical details like mountains and canals are sometimes present, sometimes not. And it’s interesting to see if land ownership changed or not when a railroad went through.

Land ownership maps can also be a way to figure out how a place got its name. Ludden Mountain, in sections 5-6 of Township 4 North, Range 2 East, takes its name from Homer Ludden.

Ludden map

Note coverage of T4N, R2E, did not begin until 1914, and no one owned Section 5 yet. By 1923, Homer Ludden owned all of Section 5, and some land around it, including the mountain that bears his name today.


Researching property history in Arizona

Phoenix renews: that’s built into the name. The city’s ashes, both figurative and sometimes literal, surround us. You don’t have to look far to see such traces. Clues abound: An empty lot has a barren sidewalk and foundation flanked by overgrown palm trees, suggesting a house.  Who lived in that house? Who built that house? What past lives has the vacant lot you pass by every day lived?

This is the first in a series of posts to inform interested researchers how to use electronic and physical resources to start answering those questions. Not everything is online, but the wealth of digital resources can help focus your research and prepare you for finding the sources behind them.

Multiple Arizona agencies, including state, county, and city interact with property records. Knowing each of them, what records they hold, and how to use them will benefit your research. For the purposes of this series, Phoenix and Maricopa County serve as examples due to ease of online access, but same basic principles apply statewide.


(By Map says Bureau of Land Management; caption at bottom says United States Geological Survey., Public Domain,

Before you get started researching, it is vital to know Arizona is a Public Land Survey State.

This system divides Arizona into a grid that subdivides into smaller grids. The large grids, called townships, each cover 36 square miles. Street atlases for Phoenix have one township per page. Townships are located using coordinates from an initial point—in Arizona’s case, the Gila and Salt River Meridian, located on Monument Hill, slightly east of the Phoenix International Raceway.

In this system, you can find any point of land north or south of that point in terms of “Township”. “Range” refers to how far east or west it is. If anyone remembers Cartesian coordinates from geometry class, Townships are the Y axis, Ranges are the X axis.

Central Phoenix, for example, is in Township One North, Range Three East (T1N R3E) from that meridian. For the curious, Arizona goes north 41 townships, south 34 townships. Ranges go east 31 townships and west 21 townships. Inside each township are 36 numbered sections, and those can subdivide into half and quarter sections. A street atlas will tell you township, range and section number.

Why are these terms important? Because most deeds in Arizona refer to this system. Nearly every arterial street in the Phoenix metropolitan area runs along these section lines. Guide books such as place name dictionaries, stage-coach encyclopedias and ghost town directories all make use of these coordinates, as well as land ownership maps. Township, range, and section number will give you the precise location of any square mile in the state, even if it’s a square mile in the middle of nowhere.

(This is Part 1 of a series written by Research Library team member Chris Seggerman. Read Part 2Read Part 3.   Read Part 4.)