The short version
When Scottsdale incorporated in 1951, the whole town fit in roughly one square mile around what is now Old Town, with about 2,000 people and Malcolm White as its first mayor. Today the city covers about 184 square miles and stretches 31 miles from its border with Tempe in the south to Carefree Highway in the north.
Almost all of that land came by annexation, a city absorbing unincorporated county land. Arizona cities do not grow automatically. Nearly every piece of today’s Scottsdale was once county desert, farmland or subdivision that the city chose to take in, usually because landowners wanted city services and the city wanted control of what got built.
How annexation works
Arizona’s annexation law is built around property owners, not voters. The city files a blank petition describing the area with the county recorder, waits 30 days and holds a public hearing, then gathers signatures. The petition succeeds when it is signed by owners of at least half the value of the property and more than half of the property owners in the area. Then the council adopts an annexation ordinance. The land must touch the city for at least 300 feet, so a city cannot leap across the desert to grab a distant parcel.
That rule favors big landowners. Because signatures are weighted by property value as well as by head count, a tract held by a single ranch family or developer can come into a city on very few signatures, while a subdivision of hundreds of homeowners takes a real campaign. Residents of the area do not get a separate election. Once annexed, the land falls under the city’s General Plan and zoning, police and fire, and, where the city extends it, Scottsdale Water. Land left out stays with the county, covered in the unincorporated county guide.
The race with Phoenix
For the first two decades, annexation was defensive. Phoenix was annexing hungrily through the 1950s, and a small town that stood still could be surrounded. Scottsdale pushed outward in every open direction. In 1962 it moved to annex the old Thunderbird II airfield north of town; Phoenix sued, claiming the published annexation map was inaccurate, and lost. The site opened as the Scottsdale Airport and Airpark in 1967, the same year the city annexed McCormick Ranch. The 1960s chapter calls it the city’s championship year.
Other communities fought the race by leaving it. Residents of Paradise Valley, fearing they would be absorbed by Phoenix or Scottsdale, incorporated their own town on May 24, 1961, with about 2,000 people and a goal of one house per acre. That decision fixed part of Scottsdale’s western edge. Carefree incorporated in 1984 as Scottsdale’s northern annexations closed in. And to the east of the older city lay the Salt River Pima-Maricopa Indian Community, a sovereign nation no city can annex; the Community guide explains why. Hemmed in on the west and east, Scottsdale grew the only way left: north. In 1975 the East Shea annexation carried the city toward Fountain Hills, from about 62 to about 89 square miles.
Drinkwater’s northern push
The decisive annexations came under Herb Drinkwater, mayor from 1980 to 1996. Between 1981 and 1984 the city added about 80 square miles, most of it empty desert rolling toward Pinnacle Peak and the McDowell Mountains. The largest single piece, 36 square miles of far-north desert, took effect on August 1, 1984, and carried the city to 181.6 square miles. The 1980s chapter and 1984 cover the approvals that followed: Gainey Ranch, Scottsdale Ranch, Desert Highlands and the long build-out of North Scottsdale.
The logic was control. Unincorporated desert was governed by county zoning, not Scottsdale’s. Annexing first meant the city could write the rules before anyone graded a lot. Those rules became the 1991 Environmentally Sensitive Lands ordinance and, above all, the McDowell Sonoran Preserve. The mayor who annexed the foothills was still in office when voters agreed to buy the mountains above them. Without the 1980s annexations there would have been no Scottsdale land to preserve.
What was left out
Annexation also defines what Scottsdale is not responsible for. Rio Verde Foothills, a rural area of large lots northeast of the city, was never annexed and remains unincorporated Maricopa County. For years many of its homes relied on water hauled from a Scottsdale standpipe. On January 1, 2023, citing drought planning, the city stopped those sales, and the story drew national attention until a separate arrangement restored supply. Legally the lesson was simple: a city’s duties stop at its limits, and people outside them answer to the county Board of Supervisors.
State law makes those edges hard to change from the other side too. A new town generally cannot incorporate within six miles of a city of 5,000 or more without that city’s consent, so unincorporated neighbors of a large city cannot easily form their own government. Scottsdale’s shape is now mostly settled. Most of its neighbors are incorporated towns, sovereign land or national forest, and the growth arguments that remain are about what happens inside the lines already drawn.