What term describes an improvement that extends onto property belonging to another person without consent?

The term that describes an improvement or structure that extends onto property belonging to another person without consent is "encroachment." This concept refers specifically to situations where a physical object, such as a fence, tree, or building, crosses the property line onto a neighboring property without permission from the owner.

Encroachments are significant in real estate law because they can lead to disputes between property owners concerning property rights, usage, and the potential for damages. Understanding encroachment is essential for property owners to navigate boundary issues and to be aware of any potential legal ramifications.

In contrast, terms like invasion and interference don't specifically pertain to the physical characteristics of a property or structures extending onto another's land. While trespass refers to unauthorized entry onto someone else's property, it does not typically apply to conditions of structures or improvements existing on land beyond the property line. Thus, "encroachment" accurately captures the legal nature of the situation described in the question.