House Numbering - United States and Canada

United States and Canada

On most streets in the United States and Canada, odd numbers are on one side and even numbers on the other. Often, the number assigned is proportional to the distance from some baseline, so not all numbers are used. On very long roads, four- or five-digit addresses are common. In some places, such as Loudoun County, Virginia, almost all addresses contain five numbers.

In cities with a grid plan of streets, addresses often increase by 100 for each cross street, though in some cities they are consecutive within each block, so that a block where one side is numbered 501, 503, 505, 507, 509, 511 is followed by a block beginning with 601.

In the Phoenix Metropolitan Area, Arizona, addresses are coordinated in a grid. The origin of the addresses is the intersection of Central Avenue and Washington Street, in Phoenix. At this point, E. Washington St. goes out to the east, W. Washington St. goes out to the west, N. Central Ave. goes out to the north, and S. Central Ave. goes out to the south. The addresses increase outward from these "baselines." Even numbered addresses are always on the north and west sides of the roads, while odds are always on the south and east sides. Outward from Central Avenue, the North/south bound roadways are named as a numbered street or avenue. One block east of Central Avenue, is 1st Street. One block west of Central Avenue, is 1st Avenue. The numbers increase as one travels further east or west, away from Central Avenue. The grid allows for easy block/address locating, For example, the blocks between Central Avenue and 1st Avenue would be the 0 West Blocks. Likewise, the blocks between 5th Street and 6th Street would be the 500 East Blocks. East/west bound roadways in the Phoenix area are not named as consecutive numbers. Rather, they are named after notable landmarks or people. However, each block is still worth or assigned 100 addresses. Many cities in the area have long since modified their addresses to relate to Phoenix's baselines. For example, the lowest numbered avenue in Glendale is 43rd Avenue, as 43rd Avenue is the most easterly border that Glendale shares with Phoenix. Major roadways in Phoenix are near-exactly one mile apart. Formed intentionally, as these sites of major roads once were routes for irrigation lines that divided vast farmland into square miles. In most cases, major north/southbound roadways are 8 Avenues/Streets is a mile. In other words, 19th Avenue and 27th Avenue are 1 mile apart. There are some exceptions to this, but it is true in most cases. For instance, 7th Street and 7th Avenue, are one mile apart, although they are about 14 numbers apart. The grid allows for easy navigation. Baseline Road, despite its misleading name, is about 7600 S (76 blocks south of Washington Street.)

Addresses may also correlate with a street-numbering system. Thus, in Cleveland, Ohio, a building with the address 900 Euclid Avenue would be at the corner of Euclid Avenue and 9th Street. Similarly, in Philadelphia, a building whose address is "1610 Walnut Street" would be located on Walnut Street between 16th and 17th streets, more-or-less across the street from 1609. In Queens, New York City, a so-called "Philadelphia Plan" uses a dash to separate the cross street number from the rest of the house number, as in 34-55 107th Street, which was once the home of Louis Armstrong.

San Francisco has several numbering systems in different districts; where these systems meet, parallel streets may be numbered in opposite directions. For example, the streets parallel to and east of Masonic Avenue are numbered northward, while Masonic and parallel streets to the west are numbered southward.

Along the Overseas Highway in the Florida Keys, house numbers indicate their distance from Mile Marker 0 in Key West. The mileage is found by dividing the house number by 1000 (for example, 77220 Overseas Highway is 77.2 miles from Mile Marker 0).

Buildings in many rural areas in the United States used to lack these kind of addresses. Instead, an old rural address might have been simply "Rural Route 3, Box 15." However, the adoption of 9-1-1 emergency systems has required the adoption of street names and house numbers in rural areas, typically numbering 1000 for each mile from the nearest town center.

In areas of rural Wisconsin, the address layout of many counties features a baseline in one corner of the county, with numbers increasing from that point and appended with a cardinal direction; for instance, an address on a north-south road 45 blocks north from the baseline is written as 'N4500', while an address 45 blocks west from the baseline on an east-west road is shown as 'W4500'. Some counties and suburban communities (such as Waukesha and the Town and City of Cedarburg) use a two-part address for both directions for easier referencing within a map and the numbering system (N4500-W4500 for instance).

Carmel-by-the-Sea, California lacks any house numbering whatsoever. Houses are referred to, instead, as (for example) "Junipero 3 SW of 10th", meaning "The third house on the west side of Junipero, south of 10th."