Antecedent Boundary Examples & Definition (Human Geography)

Antecedent Boundary examples

An antecedent boundary is a political boundary that existed before the land was populated by the current inhabitants.

For example, the boundary between the USA and Canada was drawn by the colonizers before they colonized North America.

This is the opposite of a subsequent boundary, which is drawn after a territory has been populated. Whereas antecedent boundaries are the result of political deals designed to prevent conflict, subsequent boundaries tend to be drawn to end a conflict over land.

Definition of Antecedent Boundary

In human geography, an antecedent boundary is defined as a boundary that “already existed before the present settlement in that area occurred”.

It can be a natural boundary, such as a river, that two groups of people agreed to set as their boundary. Or, it can be a boundary that doesn’t exist on the landscape but is drawn on a map. The US-Canada border is (mostly) a straight-line geometric boundary, for example, that follows a line of latitude rather than anything on the landscape.

7 Antecedent Boundary Examples

1. 49th Parallel Border

USA border

The 49th Parallel is the straight-line border between the US and Canada. It stretches from Minnesota to the west coast of the continental United States.

This border was established in the 1846 Oregon Treaty. Before that, the British and Americans had informally used the 49th Parallel as their border in the Oregon Country which was established by the Treaty of Paris.

This border was created when there was a race to the west of North America between the United States and Britain. The border agreement was put in place to ensure each side clearly knew who would own which land, preventing possible conflict later on.

While the colonizers hadn’t settled in the west, there were many Native Americans who were living along both sides of the 49th parallel whose lands were arbitrarily split by the colonizers’ borders. Thus, we can also consider this an example of a superimposed border.

2. The Gadsden Purchase (US-Mexico Border)

mexico border

In 1853, the United States reached an agreement with Mexico to purchase a large tract of land in the southwestern corner of the country. The land, which measured about 30,000 square miles, became known as the Gadsden Purchase.

The purchase added important territory to the southern route of the transcontinental railroad and provided the U.S. with a valuable port on the Gulf of California.

Although the Gadsden Purchase was widely criticized at the time as being too expensive, it has since been hailed as one of the most important real estate deals in American history.

At the time, the land was sparsely inhabited by the colonizers (notably, there were Native American tribes on both sides of the superimposed border). Today, important cities like Tijuana and San Diego push right up against the border.

3. The Boundary Waters

canadian flag

Th Boundary Waters is a section of border land between Minnesota and Ontario. It sits beside Lake Superior and is national park on both sides of the border.

This is an example of an antecedent border because there were no colonizer towns or settlements on either side of the border when it was constructed. Unlike a subsequent boundary, where the border is drawn to separate two settled groups, this border was mostly drawn to anticipate future settlement. There were very few settlements at the time the border was drawn.

To this day, the boundary waters are surrounded by national parks on both the Canadian and US sides of the border. However, there are a few very small settlements nearby such as Grand Marais, Minnesota with a population of just 1350.

The Ojibwe Native American tribe also comes from the area.

4. Alaska-Canada Border

national flag

The border between Alaska and Canada was drawn in 1898 when the United States purchased Alaska from Russia. At the time, there were no European settlers on either side of the border, although the land was cared for by Native American tribes.

The boundary was created to prevent any conflict over the land in the future. The border was originally supposed to follow the 141st meridian west but Canada (at the time, British North America) negotiated a few changes to secure better port access on the Arctic Ocean.

The border has remained largely unchanged since it was first drawn and is one of the longest uninterrupted borders in the world.

5. Australian State Borders

australian flag

The origins of the Australian state borders can be traced back to the late 18th century, when the British began colonizing the continent.

At that time, the area now known as Australia was divided into a number of small colonies, each with its own government.

Due to Australia’s enormous size, the vast majority of inland Australia was unsettled, and indeed, still remains full of wide-open spaces. Nevertheless, explorers and surveyors went on inland journeys to claim land for the various states of the future nation of Australia.

These boundaries were drawn before substantial inland settlements were established, making them antecedent borders. As with North America, the borders completely ignored the fact Aboriginal people were caring for the land for millennia before white colonizers arrived.

6. Hadrian’s Wall

hadrians wall

Hadrian’s Wall was built by the Roman Emperor Hadrian in the 2nd century AD. It marked the northern limit of the Roman Empire and was the most northern fortification in the empire.

The wall was built to prevent incursions from Celtic tribes who lived north of the border. There were very few Romans living near the northern border, and in fact, the Roman Empire had to send soldiers up to the border to create settlements and secure it.

Here, we can see that Hadrian’s wall was an antecedent border. The border was built and, to secure it, soldiers were sent to the border, where a barracks was created once every Roman mile across the length of the border.

Today, Hardrian’s wall is no longer in use, but still stands in Northern England as a relic boundary and tourist attraction.

7. Native American Reserves

indigenous people

Native Americans populated (and were custodians of) all of North America prior to European colonization. As Europeans spread westward, reserves were created, often by force or coercion, that forced Native Americans into smaller and smaller pockets of land.

Often, the land that was given reserve status was the less desirable land. However, Native Americans moved into those lands in order to avoid the violence perpetrated by the colonizers.

Thus, borders were constructed against Native Americans’ will and often in places where the Native Americans didn’t have permanent settlements. The Native Americans subsequently set up settlements within the reserves where they were safer.

This pattern: the creation of borders followed by the setting up of towns, is consistent with the definition of antecedent boundaries.


In human geography, we use the term ‘antecedent boundary’ to refer to a political boundary that has been created prior to settlement on either side of the boundary. It’s the opposite of a subsequent boundary, which is created after an area is settled, or a consequent boundary designed to separate two settled groups. Generally, antecedent boundaries are made by political negotiations between colonizers who want to avoid conflict with one another as they settle a new space.

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