Residential development is real estate development for residential purposes. Some such developments are called a subdivision, when the land is divided into lots with houses constructed on each lot. Such developments became common during the late nineteenth century, particularly in the form of streetcar suburbs.
In previous centuries, residential development was mainly of two kinds. Rich people bought a town lot, hired an architect and/or contractor, and built a bespoke / customized house or mansion for their family. Poor urban people lived in shantytowns or in tenements built for rental. Single-family houses were seldom built on speculation that is for future sale to residents not yet identified. When cities and the middle class expanded greatly and mortgage loans became commonplace, a method that had been rare became commonplace to serve the expanding demand for home ownership.
Post–World War II economic expansion in major cities of the United States, especially New York City and Los Angeles produced a demand for thousands of new homes, which was largely met by speculative building. Its large-scale practitioners disliked the term "property speculator" and coined the new name "residential development" for their activity. Entire farms and ranches were subdivided and developed, often with one individual or company controlling all aspects of entitlement (permits), land development (streets and grading), infrastructure (utilities and sewage disposal), and housing. Communities like Levittown, Long Island or Lakewood south of Los Angeles saw new homes sold at unprecedented rates—more than one a day. Many techniques which had made the automobile affordable made housing affordable: standardization of design and small, repetitive assembly tasks, advertising, and a smooth flow of capital. Mass production resulted in a similar uniformity of product, and a more comfortable lifestyle than cramped apartments in the cities. With the advent of government-backed mortgages, it could actually be cheaper to own a house in a new residential development than to rent.