Cities and Urban Land-Use Patterns and Processes
Unit 6 of AP Human Geography, worth 12–17% of the exam. 14 questions below, each with the working. Every answer was checked by a second pass before it was published.
Origin and influence of urbanisation, cities across the world, city site and situation, urban models, urban data, sustainability and urban challenges.
How this unit is tested
Start by separating description from explanation: know WHERE cities are (site, situation, hierarchy) before worrying about WHY their internal structure looks the way it does. Build a timeline in your head — agricultural surplus enabled the first cities, the Industrial Revolution triggered mass urbanization, and post-industrial/globalization forces created today's megacities and metacities. Every model in this unit answers a specific question, so before memorizing a diagram, ask what question it answers: rank-size rule and the gravity model answer 'how are cities distributed and connected across space,' while Burgess, Hoyt, Harris-Ullman, and bid-rent theory answer 'how is land used within a single city.'
When you see a map or diagram on the exam, identify which model it resembles by its distinguishing shape: concentric rings (Burgess), wedges radiating from downtown (Hoyt), scattered nodes (Harris-Ullman multiple nuclei), or a spine/sector combo with a disamenity zone (Latin American model). Do not force a US/European model onto a description of a developing-world city — the AP framework expects you to recognize when the Latin American, African (de Blij), or Southeast Asian (McGee) models apply instead, since these describe colonial legacies, informal economies, and different transportation patterns.
For urban data, practice reading population density figures, census tract boundaries, and the difference between overbounded and underbounded cities — these appear as data-analysis questions, often paired with a map or table. Finally, treat the sustainability section as applied vocabulary: know the mechanism behind each policy or problem (redlining, blockbusting, gentrification, urban sprawl, new urbanism, smart growth, squatter settlements) well enough to explain cause and effect, not just define the term.
On the exam, expect multiple-choice items that test model recognition and terminology, plus free-response prompts that ask you to apply a model or explain a process (e.g., 'explain how gentrification affects a specific neighborhood'). Practice writing one or two full sentences of explanation for every term you learn — recitation alone will not earn FRQ points.
What you have to know
Rank-size rule
In an urban hierarchy that follows the rule, the population of a city of rank n equals the population of the largest city divided by n. Significant deviation from this pattern, especially one dominant city far larger than predicted, signals a primate city distribution.
Central place theory (Christaller)
Settlements function as central places providing goods and services to surrounding market areas (hinterlands); higher-order goods require a larger threshold population and have a greater range, producing a nested hexagonal hierarchy of settlement sizes.
Gravity model
The interaction between two places is predicted to be proportional to the product of their populations and inversely proportional to the square of the distance between them, explaining flows of migration, trade, or communication.
Bid-rent theory
Land value and rent are highest at the most accessible point (typically the CBD) and decline with distance from that point, because different land uses compete for accessibility and pay accordingly.
Concentric zone model (Burgess)
A city grows outward from the CBD in a series of concentric rings, with land use and socioeconomic status changing systematically from the center (CBD) to the outer commuter zone.
Sector model (Hoyt)
Land uses and social groups grow outward from the CBD in wedge-shaped sectors that extend along transportation corridors, rather than in uniform rings.
14 practice questions
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A city grows at the point where two rivers meet, giving it fertile soil and easy water access. Which concept does this describe?
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Answer. Site
Site refers to the physical characteristics of the exact location itself, such as terrain, soil, and water access. Situation would instead describe the city's position relative to other places, like trade routes. -
A country's largest city has a population of 6,000,000. According to the rank-size rule, what would be the expected population of the 3rd-ranked city?
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Answer. 2,000,000
The rank-size rule predicts that the population of the nth-ranked city equals the largest city's population divided by n, so 6,000,000 ÷ 3 = 2,000,000. -
A city's actual 2nd-ranked city has a population far smaller than the rank-size rule predicts, while the largest city dominates the country's economy and politics. What urban pattern does this describe?
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Answer. A primate city distribution
When one city is disproportionately larger than the rest of the hierarchy predicts, that country has a primate city rather than a rank-size-rule-following hierarchy, often linked to colonial history or centralized governance. -
In central place theory, what term describes the minimum population needed to support a good or service being offered profitably?
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Answer. Threshold
Threshold is the minimum number of customers/population required for a business or service to be viable. Range is the maximum distance people will travel to obtain that good or service. -
Using a basic gravity model, if City A has a population of 500,000, City B has a population of 200,000, and they are 100 miles apart, what happens to the predicted interaction between them if the distance doubles to 200 miles, all else equal?
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Answer. The predicted interaction decreases (it falls to one-fourth of the original level)
The gravity model states interaction is proportional to the product of populations divided by the square of the distance. Doubling the distance means dividing by 2 squared, or 4, so predicted interaction drops to one-fourth of its original value. -
Which urban model describes a city growing outward from the CBD in uniform concentric rings, with socioeconomic status generally increasing toward the outer commuter zone?
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Answer. The concentric zone model (Burgess model)
Burgess proposed that cities expand outward from the CBD in a series of rings, each representing a different land use and, typically, higher socioeconomic status farther from the center. -
Explain why the Hoyt sector model predicts wedge-shaped growth rather than uniform rings.
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Answer. Because land use and social groups grow outward along transportation corridors (roads, rail lines), producing directional wedges rather than growth in every direction equally.
Hoyt argued that transportation routes attract certain land uses (like industry along rail lines or wealthy housing along scenic roads), so growth extends outward in specific directions, creating pie-slice sectors instead of Burgess's rings. -
A city has several separate nodes of growth — a university district, an airport-industrial zone, and a downtown core — none of which developed from a single center outward. Which model best describes this pattern?
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Answer. The multiple nuclei model
Harris and Ullman's multiple nuclei model describes cities that grow around several independent nodes or centers of activity rather than a single CBD, common in larger, more decentralized metropolitan areas. -
According to bid-rent theory, why does a fast-food restaurant chain typically NOT locate its restaurant in the highest-rent parcel at the very center of the CBD?
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Answer. Because the restaurant's profit per square foot cannot outbid the higher-value uses (like offices or high-end retail) that need that central accessibility more, so it locates where its lower bid-rent still covers costs.
Bid-rent theory holds that different land uses will pay based on how much value accessibility provides them; retail and office uses that profit most from central accessibility outbid uses needing less centrality, pushing lower-bidding uses further out. -
A city described in an AP exam passage has a prestigious commercial spine extending from the central market, surrounded by a zone of maturity, then a zone of peripheral squatter settlements at the edge lacking infrastructure. Which model does this describe?
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Answer. The Latin American city model (Griffin-Ford model)
The Griffin-Ford model of Latin American cities features a commercial spine extending from the CBD, concentric zones of decreasing wealth moving outward, and squatter settlements in a disamenity zone at the periphery. -
A city's legal boundary extends far beyond its built-up area, including large tracts of undeveloped farmland within official city limits. Is this city overbounded or underbounded, and why does it matter for urban data analysis?
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Answer. Overbounded; it matters because population density figures calculated using the full legal boundary will appear artificially low, misrepresenting the actual density of the built-up area.
An overbounded city includes more land within its legal limits than it actually urbanizes, which skews density statistics downward and can distort comparisons between cities with different boundary definitions. -
A bank historically refused to issue mortgages to residents of certain neighborhoods marked on maps based on racial composition, regardless of the applicants' creditworthiness. What is this practice called?
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Answer. Redlining
Redlining was the systematic denial of loans, insurance, or other financial services to residents of specific neighborhoods, historically marked in red on maps, often based on racial composition rather than actual credit risk. -
Explain the difference between urban sprawl and new urbanism as responses to city growth.
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Answer. Urban sprawl is low-density, automobile-dependent outward expansion of a city, while new urbanism is a planning approach designed to counter sprawl by creating walkable, mixed-use, higher-density neighborhoods.
Sprawl typically increases commute times, land consumption, and car dependency, whereas new urbanism principles (walkability, mixed land use, compact design) aim to reduce those effects by rebuilding community-oriented, less auto-dependent development. -
A neighborhood lacks any grocery stores selling fresh produce within a reasonable walking or transit distance, forcing residents to rely on convenience stores or fast food. What is this urban condition called?
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Answer. A food desert
A food desert is an area, often in low-income urban or rural neighborhoods, where residents have limited access to affordable, healthy food options such as fresh produce, typically due to a lack of nearby grocery stores.
What people get wrong
- Confusing site and situation — students often call a river confluence 'situation.' Site is the physical characteristics of the exact location (terrain, water, resources); situation is the location relative to other places (transportation links, trade routes). Fix: ask 'is this a feature of the ground itself, or a feature of its position relative to elsewhere?'
- Mixing up the concentric zone model and the sector model on the exam. Fix: remember Burgess = rings (uniform growth in all directions), Hoyt = wedges (growth follows transportation routes, so it is directional, not uniform).
- Assuming every city follows the rank-size rule. Fix: check whether one city is disproportionately larger than the rest — that pattern is a primate city, the opposite of a rank-size-rule-following hierarchy.
- Treating gentrification, blockbusting, and redlining as interchangeable. Fix: redlining denied loans to minority neighborhoods (mid-1900s), blockbusting was real-estate agents provoking panic selling to profit from racial turnover, and gentrification is the more recent process of wealthier residents moving into and renovating a lower-income urban neighborhood, raising property values and often displacing original residents.
- Applying Burgess, Hoyt, or Harris-Ullman to describe cities in Latin America, Africa, or Southeast Asia. Fix: recognize when a question describes a colonial core, informal settlements at the periphery, or a market-based street layout, and switch to the Griffin-Ford, de Blij, or McGee model instead.
- Forgetting that bid-rent theory explains why commercial land uses occupy the highest-rent CBD despite the cost — because accessibility, not low cost, drives their location decision. Fix: connect bid-rent curves to WHY each land use (commercial, industrial, residential) locates where it does, not just that rent decreases outward.
Drill this unit until it sticks
These questions come back on a schedule built from what you get wrong, alongside the rest of AP Human Geography. Free, and no account needed to start.