Street Numbering Systems in the U.S.: How They Work and Their Variations

Introduction to Street Numbering Systems

In the United States, street numbering systems can vary significantly from one city to another. This article explores how residential street numbers work, with a focus on specific examples in King County, Washington, and Manhattan, New York.

Understanding Street Numbers in King County, Washington

Street numbering in King County, Washington, is based on a reference point in downtown Seattle. For example, if a address is 277xx, it means the property is approximately 277 blocks south of an east-west line through that reference point. Similarly, a house on 215 Av SE is about 215 blocks east of a north-south line through the reference point. These addresses provide a good indication of the location within the county. (Explore Seattle on Google Maps)

Street Numbering Systems in Manhattan, New York

In Manhattan, street numbering is quite different. Many house numbers run almost consecutively. This means that moving from 800 5th Avenue to 900 5th Avenue can be a four-block walk. This variation in numbering systems underscores the diversity of American address systems.

General Principles of Addressing in the U.S.

Michael James, a developer, explains that west of the Mississippi River, developers typically number each block sequentially from a point of origin (POO) at or near the center of town. In this system, odd numbers are on one side of the street and even numbers on the other. For example:

On the odd-numbered side (north/south for east-west streets, and east/west for north/south streets), the closest property to the POO would have an address number closest to the POO. For instance, in a 500 block, the closest property would be 500 or 501, and the furthest would be 590 or 591. On the even-numbered side, the numbers would be 500, 510, 520, 530, 540, 550, 560, 570, 580, and 590. This system allows for flexibility in adding addresses in case of subdivided properties or changes in the type of property, such as converting single-family homes into duplexes.

Addressing Challenges and Solutions

While the general rules are often followed, there are no solid universal rules that govern address numbering. For example, a house might not conform to the rule that suggests even numbers are on one side and odd numbers on the other. There is a recognition that, like many aspects of American life, developers often choose to do what they believe is best.

Additionally, the absence of posted house numbers can make finding a specific property more challenging. Residents often have to rely on unique features, such as the presence of flags or vehicles in the driveway, to identify homes without visible numbers.

The emergence of smartphone mapping applications has significantly simplified the task of finding a specific house, but this relies on having a reliable source of address information.

Concluding Thoughts

Street numbering in the U.S. is a complex yet fascinating subject. While there are general principles, individual cities and even blocks can have unique systems. Understanding these systems can help in navigating and finding specific properties, whether through traditional means or modern technology.

For readers interested in exploring more, here are some useful resources:

The Odd-Even Rule: North, South, East, West - How Do Street Numbers Work in Different Cities? The American Addressing System Explained Where are you on the Number Line?