Monument Hill • City of Avondale/Gila River Indian Reservation
• Maricopa County
• Arizona Public Lands Surveyor's Origin

Monument Hill as seen from Avondale Road where it crosses the Gila River

Phoenix International Raceway

The exact surveyor's origin

Disks denoting the four townships that start from here

Close-up of other plaques, plus me stepping into four different townships at the same time

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Prominence Peaks


Date: December 9, 2015 • Elevation: 1,155 feet • Prominence: 155 feet • Distance: 0.4 mile • Time: 30 minutes • Gain: 175 feet • Conditions: High clouds, mild

Monument Hill is a small, completely anonymous little bump located along the south banks of the Salt River, in the northernmost foothills of the Sierra Estrella. The hill has two claims to fame: it abuts the Phoenix International Raceway (PIR) and is often filled with spectators during the big NASCAR events, and it is the location of the Arizona Public Lands Surveyor’s Origin monument (hence the hill’s name).

My interest trends more toward the hill’s second claim to fame, but for such a small hill, I couldn’t work up the momentum to drive over 50 miles each way just to spend thirty minutes hiking it. The only plausible way I was going to visit it was as part of a bigger journey. I had a day open, so I left early in the morning and drove to the far-west fringes of metro Phoenix, hiking the Palo Verde Hills, which didn’t take long. On the way back home, I would detour and finally visit the monument.

Since the hill is on private property (that of the PIR), I called ahead the day before to confirm that public access is permissible. They are fine with people hiking the hill as long as there’s no actual event going on. All they ask is to check in with the guard at Gate 8, nearest the little hill. From Interstate-10, I exited onto Avondale Road, then south about six miles. Avondale Road then crosses the Salt River over a bridge and bends west. I entered onto the PIR property, drove to Gate 8, told the guard what I wanted to do, and he pointed to where I could park. I parked at the end of the pavement near a gate and fencing that line the wetlands of the Salt River.

The trail starts here. I followed it up, going north, then hard right, now going south, then up slope to catch a road cut that leads to the top. The hike took me about 10 minutes, covering about 0.2 mile and 175 feet of gain. There was the marker, slightly beaten up from past visitors. There was glass from broken bottles plus general food wrappers. The views were nice. I took images of empty PIR, plus the marker and its disks and plaques. The hike down went quickly, and the whole journey lasted about a half hour. From here, I drove back to the interstate and on home.

For most of history, land parcels were described using natural features such as trees, creeks, mountain ridges, rocks, and so forth, to define the land’s boundaries. This system is called metes and bounds. It is prone to interpretation and error, and does not work well in areas where there are few obvious natural features. After the Louisiana Purchase, Thomas Jefferson and subsequent presidents realized the need for a more systematic system of subdividing the land, especially now with such a large tract of land under American jurisdiction.

The method used is called the Public Lands Survey System, and divides the land into a gigantic grid of mile-square parcels called sections. Thirty-six sections are groups into a six-mile by six-mile block and called a township. The townships then are “stacked” into rows trending east-west, called tiers. When viewing a map of townships, the columns are referred as range. This all needs a starting point, and in each state, a surveyor’s origin is selected (sometimes, more than one if the state is very large). Arizona’s surveyor’s origin was selected to be atop this little hill back in the 1850s. The hill was likely selected because it is nearest the confluence of the Salt and Gila Rivers.

Looking at a map of Arizona, a horizontal (east-west) line is drawn, called the baseline, and a vertical line (north-south) is drawn, called the principal meridian. These act like the x and y-axes (respectively) of a coordinate axis system. The township’s range is the x-coordinate, its tier is the y-coordinate, and all tiers and ranges count from one, designed North or South for tiers, East or West for ranges. Within a township, the sections are numbered 1-36 starting in the top right corner and ending in the lower left corner in a continuous manner (right to left, then left to right, and so on). The sections are then subdivided into halves, quarters, eighths, and so on. A parcel of land one-eighth of a mile by one-eighth of a mile covers 1/64th of a section (hence, 1/64th of a square mile) and is defined as 10 acres. This is usually the smallest subdivision of land. Developers may subdivide the land further if they so desire.

Thus, when you buy land or a house or anything attached to the ground, which most things tend to be, somewhere in the deeds office is a cryptic string of characters describing where your land is, exactly. For example, you may see “West ½ of North ½ of Section 3, T3N R4W”. This means that you go to the township in Tier 3 North, Range 4 West, find Section 3 (it’ll be in the top row, third from right), find the north half, then find the west half, and that’s your plot of land. In this way, land can be bought and sold more efficiently. It makes land a true commodity.

Almost the entire western United States is plotted into sections. Some exceptions are places like the Grand Canyon, some Indian Reservations, military property, and old land grants that predate the United States. Arizona is no exception. The main boulevards in Phoenix all follow section boundaries, and this explains why the Avenues count up by 8 each mile when travelling along Interstate-10, since the subdividing went to the eighths way back in the olden days.

An excellent book on the history of this subject is Andro Linklater's Measuring America: How the United States Was Shaped By the Greatest Land Sale in History. It is fascinating, if you're into this sort of thing.

I arrived back to Scottsdale and stopped for a lunch, before going to my humble residence in Section 7 of Tier 3 North, Range 5 East.

(c) 2015 Scott Surgent. For entertainment purposes only. This report is not meant to replace maps, compass, gps and other common sense hiking/navigation items. Neither I nor the webhost can be held responsible for unfortunate situations that may arise based on these trip reports. Conditions (physical and legal) change over time! Some of these hikes are major mountaineering or backpacking endeavors that require skill, proper gear, proper fitness and general experience.