gridiron plan

urban planning

Also known as: orthogonal grid system

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

June 29, 2026

Quick Summary

The gridiron plan is an urban planning strategy that uses a rectilinear or orthogonal grid system for city layout. This approach, characterized by streets intersecting at right angles, has ancient origins, with evidence found in cities across China, India, Egypt, and the Americas.1

In the Americas, the grid plan was notably adopted by Spanish and Portuguese settlers for new cities and the adaptation of existing Amerindian capitals. This system was eventually codified by the Laws of the Indies, a set of guidelines for urban development in Spanish America. A prominent early example in the United States is William Penn's plan for Philadelphia in 1682, which facilitated land markets by establishing standard lot sizes. While simple and efficient for land division, the grid plan does not always account for topography.21

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

3 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

urban planning
Early history
cities, however, was the rigid grid plan of Philadelphia, designed by William Penn (1682). This plan traveled west with the pioneers, since it was the simplest method of dividing surveyed territory. Although it took no cognizance of topography, it facilitated the development of land markets by establishing standard-sized lots that…
Read More
cities, however, was the rigid grid plan of Philadelphia, designed by William Penn (1682). This plan traveled west with the pioneers, since it was the simplest method of dividing surveyed territory. Although it took no cognizance of topography, it facilitated the development of land markets by establishing standard-sized lots that…
Read More

ancient Italic people
Archaeological evidence
…out a city with a grid plan; it was oriented according to the compass, emphasizing a principal north-south street and including one or more major east-west streets. The ritual involved in thus laying out a town, complete with walls, temples, and other sacred areas, was known to the Romans as…
Read More
…out a city with a grid plan; it was oriented according to the compass, emphasizing a principal north-south street and including one or more major east-west streets. The ritual involved in thus laying out a town, complete with walls, temples, and other sacred areas, was known to the Romans as…
Read More

Latin American architecture
The new urban strategy: Checkerboard plans and the Laws of the Indies
…America to apply a regular orthogonal grid system, an urban design model that became the norm for all the Americas. Origins of this grid-based urban plan had previously been found in varied sources dating back to the colonies of the Greek empire and then in Renaissance treaties. Such sources may…
Read More
…America to apply a regular orthogonal grid system, an urban design model that became the norm for all the Americas. Origins of this grid-based urban plan had previously been found in varied sources dating back to the colonies of the Greek empire and then in Renaissance treaties. Such sources may…
Read More