Editing Border (section)

== Border construction and crossings ==
{{Main|Boundary marker|Border barrier|Separation barrier}}
{{See also|Border outpost|Observation post|Buffer zone|Defensive wall|Barricade|Wall|Fence|Landmark}}
[[File:Anarchist anti deporation protest.jpg|thumb|[[Anarchist]] protest against borders and deportations in [[Minneapolis]], [[United States]]]]
While many borders are based on specific natural landscape features, some borders have additional man-made infrastructure. Fencing is used for security reasons, mainly to prevent unauthorised activity between the borders, including the travelling and transport of humans and goods.<ref>{{Cite web |title=Border Wall System - Frequently Asked Questions {{!}} U.S. Customs and Border Protection |url=https://www.cbp.gov/border-security/border-wall/border-wall-system-frequently-asked-questions? |access-date=2025-02-08 |website=www.cbp.gov |language=en}}</ref><ref>{{Cite web |date=5 June 2024 |title=Australia's biosecurity and border controls |url=https://www.smartraveller.gov.au/while-youre-away/biosecurity-border |access-date=8 February 2025 |website=SmartTraveller}}</ref> In a state of increased tension, borders may also be heavily fortified, with defensive infrastructure being built.<ref>{{Cite web |date=2007-10-12 |title=" The Berlin wall : History of Berlin Wall : Facts " |url=http://die-berliner-mauer.de/en/fakten.html |access-date=2025-02-08 |website=die-berliner-mauer.de |archive-url=https://web.archive.org/web/20071012011801/http://die-berliner-mauer.de/en/fakten.html |archive-date=2007-10-12}}</ref> Crossings may be built into a border to allow for regulated crossing into such territory.<ref>{{Cite web |title=Australian Border Force Website |url=https://www.abf.gov.au/entering-and-leaving-australia/crossing-the-border/overview |archive-url=http://web.archive.org/web/20241204171728/https://www.abf.gov.au/entering-and-leaving-australia/crossing-the-border/overview |archive-date=2024-12-04 |access-date=2025-02-08 |website=Australian Border Force Website |language=en-AU}}</ref>

=== Crossings and transition ===
{{Main|Border checkpoint|Port of entry}}
{{See also|Border town|Trading post|Port|International Airport|Custom house}}
[[File:Nuijamaa border crossing 2017 03 (cropped).jpg|thumb|The car traffic on the [[Finland|Finnish]] side of the [[Finland–Russia border|Russian border]] at the Nuijamaa Border Crossing Point in [[Nuijamaa]], [[Lappeenranta]], Finland]]
Even the most fortified borders reserve specific places to allow crossing. The many forms of borders have different ways of enabling and controlling passage.

=== Movement and permeability ===
{{Main|Border control|International migration|Migration (ecology)|Seed dispersal|Pollution}}

Borders can have a significant impact on and function for movement. It can enable and stop movement, across as well as along borders.

The [[Permeability (spatial and transport planning)|permeability]] of borders depends on its construction, availability of crossings, regulation and types or scope of activity. The permeability can vary, borders can be barriers for humans, but also for [[animal migration]] or types of [[pollution]].