The Origin and Influences of Urbanization | AP HG Unit 6 Lesson 6.1

Learning Objectives

By the end of this lesson, students will be able to (per CED LO PSO-6.A):

Explain the processes that initiate and drive urbanization and suburbanization (per LO PSO-6.A).
Define site and situation and explain how each influences the origin, function, and growth of cities (per EK PSO-6.A.1).
Identify the six CED-named drivers of urbanization: transportation, communication, population growth, migration, economic development, and government policies (per EK PSO-6.A.2).
Apply site and situation to explain the origin of three specific cities (Cairo, Singapore, Chicago).
Compare similarities and differences in urbanization processes between different locations and time periods (per Skill 2.D).

Key Concepts

Per CED LO PSO-6.A, students must "explain the processes that initiate and drive urbanization and suburbanization." The CED breaks that into two EKs: (1) site and situation influence the origin, function, and growth of cities; and (2) six specific drivers influence urbanization. This lesson walks through each.

What is urbanization?

Urbanization is the process by which a country's population shifts from rural to urban places. It happens three ways: rural-to-urban migration, natural increase within cities, and reclassification (villages becoming urban as they grow). In 1800, only about 3 percent of the world population lived in cities. By 1950 it was ~30 percent. By 2026 it is ~57 percent and still rising, led by Asia and Africa.

"A city’s origin, function, and growth are shaped by site and situation, while urbanization is driven by changes in transportation and communication, by population growth and migration, by economic development, and by government policy."AP HG CED, EKs PSO-6.A.1 and A.2 (paraphrased)

Why cities form where they do

Cities do not appear randomly. They form where the site — the physical characteristics of the place itself — allows settlement (water, arable land, defensibility, topography). And they grow because the situation — the location relative to other places — connects them to useful things (trade routes, political centers, resource hinterlands, accessible markets). Some cities owe their existence more to site; others more to situation. Most owe both.

Site and Situation (EK PSO-6.A.1)

Per EK PSO-6.A.1, site and situation influence the origin, function, and growth of cities. Both concepts matter for the AP HG exam.

Internal

Site

The Physical Characteristics of the Place

Site is what is there. Waterways, soil, climate, topography, elevation, defensibility, access to fresh water, drainage. Site answers: could people physically settle here?

Example: Manhattan's deep harbor and bedrock enabled both shipping and skyscrapers

External

Situation

The Location Relative to Other Places

Situation is where it sits in a network. Proximity to trade routes, other cities, ports, political centers, and resource regions. Situation answers: why is this particular spot valuable?

Example: Chicago sits at the southwest corner of the Great Lakes, linking the Midwest to the East

The three classic city-origin types

Throughout history, cities have formed at certain recurring situations.

Water Transport

Natural harbors, river mouths, fords, confluence points, head of navigation. Historically the most common origin: New York, London, Shanghai, Rotterdam, Cairo.

Example: London founded where the Thames was narrow enough to bridge but deep enough for ships.

Break-of-Bulk Points

Places where cargo must be transferred between modes (ship to rail, rail to truck, ship to land). Value added in handling; cities grew around these transshipment functions.

Example: Chicago as rail-to-lake shipping transfer point for grain and cattle.

Defensive / Political

Defensible hilltops, island positions, or sites chosen by rulers for administrative or symbolic reasons. Capitals often chosen more for situation than site.

Example: Brasília founded 1960 in the interior as a deliberate political act.

When situation changes

A city can have identical site across centuries but see its situation transformed by technology or politics. The Erie Canal (1825) turned New York from one East Coast port among many into the gateway to the American interior. Singapore's situation leaped when the Suez Canal opened in 1869. A city's fortunes can rise or fall when the network around it changes even if its site does not.

Six Drivers of Urbanization (EK PSO-6.A.2)

Per EK PSO-6.A.2, "changes in transportation and communication, population growth, migration, economic development, and government policies influence urbanization." All six are CED-named.

1. Transportation

Rail (1830s), streetcars (1880s), subways (1890s), cars (1920s), and highways (1950s) each reshaped where cities could grow. Better transport lets cities spread farther and exchange more with hinterlands.

Example: US Interstate Highway Act (1956) accelerated suburbanization.

2. Communication

Telegraph (1840s), telephone (1870s), and internet (1990s-) reduce the need for physical co-location but also concentrate high-value command functions in world cities. Net effect is complex.

Example: Fiber-optic hubs reinforce world-city dominance.

3. Population Growth

Where populations grow fast, urban populations grow even faster. Most of the world's population growth since 1950 has happened in or near cities; natural increase is a major driver of urbanization separate from migration.

Example: Lagos, Nigeria from ~1M (1970) to ~15M+ (2024).

4. Migration

Rural-to-urban migration drove the industrial revolution and continues today. Classic push factors: low farm income, land pressure. Pull factors: wage jobs, education, services.

Example: ~300M rural-to-urban migrants in China since 1990.

5. Economic Development

Industrialization and services concentrate in cities, drawing workers. As GDP per capita rises, a larger share of labor shifts from agriculture to urban manufacturing and services.

Example: South Korea's ~20% urban (1950) → ~81% urban (2024) alongside economic takeoff.

6. Government Policies

Decisions about where to invest, zone, subsidize, or restrict movement shape urbanization. Examples: China's hukou system restricting rural migration; Brazil's Brasília project; Singapore's housing policy.

Example: Chinese hukou reform (2014-) gradually permitted more urban residency.

Drivers in combination, not isolation

The six drivers rarely operate alone. Classic late-twentieth-century Latin American urbanization combined population growth (driver 3), rural land pressure pushing migration (driver 4), and industrialization pulling labor toward cities (driver 5). Each driver reinforced the others. On the AP exam, strong answers identify multiple drivers acting together.

Country Case Studies

Four cases illustrating site, situation, and the drivers of urbanization.

Egypt · Cairo: Classical Site and Situation

Cairo metro ~22M; Nile delta apex

Cairo sits at the apex of the Nile delta — a site with year-round fresh water, fertile silt, and a natural point where overland North African traffic meets Nile river traffic. Its situation linked the Mediterranean to the Red Sea via the Nile since pharaonic times. The Fustat (641) and Cairo (969) foundings each refined this site-situation logic. Today Cairo is one of the largest cities in Africa.

Country page →

Singapore · Situation Is Everything

~5.9M population; #2 world port by throughput

Singapore has a limited site — a small swampy island, no fresh-water rivers, minimal arable land. Its overwhelming asset is situation: it commands the southern exit of the Strait of Malacca, through which roughly 25 percent of world trade passes. Raffles founded the trading post in 1819 explicitly for this situation. Modern Singapore's wealth comes from finance, shipping, and re-export, all situation-driven.

Country page →

United States · Chicago: Break-of-Bulk Genius

Metro ~9.4M; rail + Great Lakes hub

Chicago's site is a flat swamp on Lake Michigan. Its situation is unmatched: the lake touches the eastern edge of the vast Great Plains grain belt, forcing all east-west movement to funnel through Chicago. The Illinois and Michigan Canal (1848), then the railroads, turned it into the world's great grain, lumber, and cattle transshipment city. Classic break-of-bulk origin.

Country page →

Nigeria · Lagos: Population-Driver Urbanization

Lagos metro ~15-17M; fastest-growing in West Africa

Lagos illustrates EK PSO-6.A.2's drivers operating at scale. Post-1970 oil wealth (economic development), natural increase (population growth), and rural-to-urban migration (migration) combined to push Lagos from ~1M in 1970 to ~15-17M by 2024. The site (coastal lagoon) and situation (West African trade gateway) are favorable; the scale of the drivers is what turned it into Africa's largest city.

Country page →

Discussion Questions

Per EK PSO-6.A.1, site and situation influence the origin, function, and growth of cities. Pick a city you know and describe its site and its situation. Which one contributes more to its current importance?
Can a city's situation change without its site changing? Give an example from this lesson and explain the mechanism.
Per EK PSO-6.A.2, which of the six drivers do you think is most responsible for current urbanization in sub-Saharan Africa? Which for East Asia? Do they differ, and why?
Suburbanization is mentioned in LO PSO-6.A alongside urbanization. Which of the six drivers best explains post-1945 US suburbanization? Defend.
Apply Skill 2.D: compare the origin and growth of Cairo and Chicago. What is similar and what differs?

Classroom Activities

35 min

Site + Situation Diagnosis

Each pair receives one city (Istanbul, Vancouver, St. Louis, Johannesburg, Mumbai, or Dubai). They write a one-page brief: (1) what is the site? (2) what is the situation? (3) which one best explains the city's current role? Defend with data.

CED EK: PSO-6.A.1

45 min

Six-Driver Timeline

Groups pick one country and build a 200-year urbanization timeline, identifying when and how each of the six CED drivers (transport, communication, population, migration, economic dev, policy) operated. Deliverable: annotated timeline + 3-minute presentation.

CED EK: PSO-6.A.2Deliverable: Timeline + presentation

Vocabulary

Urbanization

The process by which the share of a country's population living in urban areas grows.

LO PSO-6.A

Suburbanization

Movement of population from central cities to surrounding lower-density residential areas.

LO PSO-6.A

Site

The internal physical characteristics of a place (topography, water, soil, climate).

EK PSO-6.A.1

Situation

A place's location relative to other places and to transport networks.

EK PSO-6.A.1

Break-of-Bulk Point

Location where cargo must be transferred between transport modes; often an origin for major cities.

Builds on EK PSO-6.A.1

Rural-to-Urban Migration

Movement of people from countryside to cities; major driver of urbanization.

EK PSO-6.A.2

Natural Increase

Population growth from births exceeding deaths; contributes to urbanization where urban populations grow.

Builds on EK PSO-6.A.2

Reclassification

When previously rural areas become defined as urban as their populations grow past a threshold.

Builds on LO PSO-6.A

Hinterland

The surrounding rural region whose trade, labor, and resources a city draws on.

Builds on EK PSO-6.A.1

Hukou System

Chinese household registration policy that historically limited rural-to-urban migration; government-policy driver example.

EK PSO-6.A.2 (policy)

Urban Functions

The activities a city performs: trade, manufacturing, administration, education, culture; shaped by site and situation.

EK PSO-6.A.1

Push and Pull Factors

Push factors drive people away from rural areas; pull factors attract them to cities.

Builds on EK PSO-6.A.2

Standards Alignment

Draft alignment — pending educator review. AP HG codes correspond to the official College Board Course and Exam Description (Effective Fall 2020, V.1). Statements below are paraphrased in CountryReports' own voice; refer to the College Board's published CED for verbatim wording.

AP Human Geography CED-ALIGNED

Suggested Skill

2.DAccount for the importance of geographic similarities and differences across locations and across time.

Enduring Understanding

PSO-6The presence of cities and how they grow varies from place to place because of physical geography and resources.

Learning Objective

PSO-6.AAccount for the processes that begin and propel urbanization and suburbanization.

Essential Knowledge

PSO-6.A.1A city's origin, function, and growth are shaped by site and situation.

PSO-6.A.2Urbanization is driven by changes in transportation and communication, by population growth and migration, by economic development, and by government policy.

National Cross-Walks

NCSS Theme 3People, Places, and Environments — how human-environment interaction is supported by maps and spatial analysis.

NCSS Theme 8Science, Technology, and Society — including the technology behind cartography and GIS.

C3 D2.Geo.4.9-12Drawing on maps and other representations, account for the relationships between locations and shifts in environmental features.

C3 D2.Geo.8.9-12Assess how economic, political, and social decisions affect the demographic makeup of communities.

CCSS RH.11-12.2Identify the central ideas or information of a primary or secondary source (such as religious texts or language atlases).

Discipline-Specific National Standards

Geography for Life · Std 12The processes, patterns, and roles of human settlement.

Geography for Life · Std 3Examining how people, places, and environments are spatially arranged across the surface of the Earth.

Nat Std Economics 4People react to positive and negative incentives in foreseeable ways — applied to urbanization incentives.

Other Assessment Frameworks

AP World History Unit 5Revolutions — the industrial revolution as a force behind urbanization.

AP MacroeconomicsInternational trade, currency exchange rates, and the balance of payments.

IB Geography SL/HLCore Theme: geographic perspectives — examining map types and projections.

AP® and Advanced Placement® are registered trademarks of the College Board. The College Board was not involved in the production of this material and does not endorse it. Standards statements above are paraphrased; codes refer back to the official College Board CED, the NCSS C3 Framework, the Common Core State Standards, and other cited frameworks.

AP Practice Questions

Multiple Choice Sample

1Question: Per CED EK PSO-6.A.1, which of the following best describes the difference between site and situation?

(A) Site is a city's population; situation is its area.
(B) Site is the internal physical characteristics of a place; situation is its location relative to other places.
(C) Site is economic; situation is cultural.
(D) Site is current; situation is historical.
(E) Site is urban; situation is rural.

Correct: (B). EK PSO-6.A.1 establishes site as internal physical characteristics and situation as location relative to other places.

Free-Response Question Stem

2Per CED LO PSO-6.A, urbanization is driven by multiple factors. (A) Define site and situation per EK PSO-6.A.1 and give one example of each. (B) Identify THREE of the six drivers of urbanization named in EK PSO-6.A.2 and describe each. (C) Apply one driver to a specific country and explain how it shaped urbanization there. (D) Apply Skill 2.D: compare urbanization in two regions (e.g., post-1950 Latin America vs. post-1978 East Asia) using at least two of the six drivers.

Scoring: 2 points for site + situation definitions + examples; 3 points for three named drivers with descriptions (transportation, communication, population growth, migration, economic development, government policies); 1 point for country-specific application (Nigeria pop growth + migration; China policy + economic dev; South Korea economic dev); 2 points for regional comparison using multiple drivers.