A defined boundary is a legally established line that marks the limits of a political unit or territory. These boundaries are often described in legal documents or treaties. 

Defined boundaries are important for establishing: 

Sovereignty: The sovereignty of states 

Jurisdiction: Clear jurisdictions for governance, resource management, and territorial claims 

Identity: Identity among political entities or states 

Clarity: Clarity in political organization 

Boundaries can be physical, conceptual, or natural: 

Physical boundaries: Natural barriers between two areas, such as rivers, oceans, deserts, or mountain ranges 

Conceptual boundaries: Lines on a map or a legal demarcation 

Natural boundaries: Boundaries based on natural features, such as rivers, mountains, or deserts 

Boundaries can be a source of conflict or tension, especially when there are disputes over their location.

Defined boundaries are established by a legal document. Delimited boundaries are drawn on a map. Demarcated boundaries are identified by physical objects, like walls, signs, and fences. Any boundary is also determined by either natural or geometric lines.

Borders are generally defined as geographical boundaries, imposed either by features such as oceans and terrain, or by political entities such as governments.

Defined borders are the clearly established and recognized boundaries that delineate the territorial limits of a state or political entity.

The world is full of boundaries but not all look or function the same...

A boundary is an invisible line that marks the extent of a state's territory. Boundaries are learned, accepted and occasionally challenged. But not all boundaries function the same.

Boundaries first begin by DEFINING where the lines will be set. Definition, in political geography, is the written legal description (as in a treaty-like document) of a boundary between two countries or territories. 

The Berlin Conference was a conference regulating European colonization and trade in Africa, held in Berlin, Germany in 1884. It began by settling a dispute over the Congo between Belgium, France and Portugal. It resulted in the “Scramble for Africa,” and the subjugation of African nations. The "General Act of the Berlin Conference of West Africa" was the legal definition of which regions European powers had exclusive rights over.

Article 1 of the 1933 Montevideo Convention famously includes “a defined territory” among the four qualifications for statehood. This requirement is seen as reflective of customary law by many, whereas others hold the view that a defined territory is a pre-legal condition for exercising sovereignty in a community of equal states. Even if this can be doubted, based on the observation that some territorial entities in world history have fared well even with no clear understanding of their precise borders, it is true that the current international society has accepted the idea that boundaries are necessary. All in all, the idea that a “defined territory” is a prerequisite for statehood must allow for the possibility of some segments of the frontier line being undetermined (here and in the following we use the words “boundary,” “border,” and “frontier” interchangeably). This bibliography lists a number of items as starting references for research on the concept of a boundary, its history, its application in specific geographical contexts, and its role in interstate disputes (having in mind that the distinction between boundary and territorial disputes is a matter of quantity rather than quality). The point of view is primarily legal, but other perspectives—sociological, historical, geographical, anthropological, and political, inter alia—have given rise to a copious literature, including no less than five journals devoted to borders and border areas (Journal of Borderlands Studies; International Journal of Migration and Border Studies; Border and Regional Studies; Borders in Globalization Review; and Journal of Territorial and Maritime Studies). Since these approaches may be fruitful in light of what is usually known as cross-fertilization among different disciplines, non-legal studies are occasionally referred to, convinced as we are that lawyers should not ignore the origins, consequences, and other “surroundings” of their objects of study. Conversely, we leave out those subjects that are extensively covered by other Oxford Bibliographies articles, such as “Territorial Title”, “Secession,” and, save for some scattered bibliographic elements, “Uti Possidetis Iuris” (but other entries are quoted below). Some internal cross-references, to be found in introductory paragraphs and elsewhere, are present, given the unavoidable overlapping between sections.

Boundaries and Geography

Interest in boundaries in an international law perspective breeds interest in the actual position of boundary lines, both on maps and on the ground. Unfortunately, no official cartographic work is available; even if it were, the issue of its constant update would remain (for instance, the complete International Boundaries: A Geopolitical Atlas, authored by Ewan W. Anderson and published by Routledge, dates back to 2003). The problem could be tackled by making geographical data available online, which is done by the World Bank Official Boundaries project (also at an intra-state level, which would prove useful when uti possidetis becomes applicable) and other databases. The United Nations Initiative on Global Geospatial Information Management aims to improve states’ capacity to collect topographical data, whereas the mandate of the United Nations Group of Experts on Geographical Names includes addressing the issue of cartographic denominations (which may be relevant in boundary disputes). One has to keep in mind, though, the disclaimer repeated by these organizations: designations and maps do not imply the expression of such bodies’ opinion concerning the delimitation of boundaries. However, a role of these institutions in boundary-marking is advocated by Claussen 2009, especially by making use of advanced technological tools. Geographers like Samuel Whittemore Boggs and Stephen B. Jones, in turn, have stressed the difficulty of carrying out actual demarcation starting from delimitation as set out in treaties and maps (Whittemore Boggs 1940, Jones 1943, and Jones 1945). Speaking of inter-state agreements and border lines drawn over maps, even if no atlas exists that can provide reliable and up-to-date information on boundaries, especially those that are contested, the international lawyer may be interested in works—such as Tertrais and Papin 2016 and Nikolic 2019—which focus on specific boundary settings, chosen for their saliency or strangeness. Far from being a mere divertissement, this literature shows how political needs may shape boundaries in unexpected ways. For a longer historical account, still rich in maps, see Foucher 1991; it could perhaps have featured in the next section (General Overviews), so it can be seen as the trait d’union with it. https://www.oxfordbibliographies.com/display/document/obo-9780199796953/obo-9780199796953-0244.xml 

Defined Boundary. boundary is created in agreement between two parties in a treaty or other legal document · Delimited Boundary · Demarcated Boundary · 4 Purposes ...

Defined boundaries are legally established lines that mark the limits of a country's territory, and they are essential for establishing a country's sovereignty, identity, and jurisdiction. They can be described in legal documents or treaties, and can include physical markers like walls, fences, or signs, or abstract legal descriptions. 

Defined boundaries are important for a number of reasons, including: 

Preventing disputes

Defined boundaries help to ensure clarity in political organization and prevent disputes. 

Establishing jurisdiction

Defined boundaries help to establish clear jurisdictions for resource management, governance, and territorial claims. 

Influencing migration patterns

Defined boundaries can affect migration patterns, trade, and cultural interactions between nations. 

Shaping identity and governance

Defined boundaries can shape the identity and governance of states. 

Boundaries can be natural or geometric, and can be influenced by historical conflicts, treaties, and negotiations. For example, some political borders are based on natural features like rivers, mountains, or deserts. The Niagara River, the Rio Grande, the Rhine, the Mekong, and the Ichamati river are all examples of natural borders that have been used to define political borders.

Defined boundaries refer to the specific and clear demarcation of a territory, outlining the limits of political control and governance.

A defined boundary is a legally established line that marks the limits of a particular territory or political unit, often described in legal documents or treaties.

Boundaries are defined lines or limits that demarcate the territorial extent of a political entity, such as a country, state, or region. They play a crucial role in political geography by determining jurisdiction, governance, and the relationship between different political entities.

Geographic boundaries are defined lines that separate different political or territorial entities, such as countries, states, or regions. These boundaries can be physical, like rivers or mountains, or artificial, created through legal agreements and treaties

Rivers, coastlines ( on the Great lakes, for example) , and mountains. These are all natural boundaries.