## August 10, 2010

### Unit Signs

As you walk along the streets in Washington, D.C., you'll notice that signs at corners give not only the street name but also a numerical indicator representing the numbers assigned to a given block—typically in multiples of 100.

So, as you approach the U.S. Capitol, you're likely to see signs saying 500, 400, 300, 200, 100. Then what happens? Do you get 000 or 00?

Curiously, the chosen designation for the zero-order block is UNIT.

I wonder how this designation came about (and whether it even makes sense in this context). So far, I haven't been able to find anything on its history. And what happens in other cities?

My thanks to Joshua Zucker for pointing out this unusual feature of the Washington streetscape.

Photos by I. Peterson

Anonymous said...

“The "unit block" of a street in DC is the first block from the quadrant dividing line. The house numbers are single or double digit. The next block is the 100 block, which in most cities is the first block of the numbering system. For example, the old main post office in DC was at 2 Mass. Ave., NE. It was on the northeast corner of North Capitol Street (the dividing line between east and west) and Massachusetts Avenue. Since it was between No. Capitol and First Street NE, it was in the unit block. The addresses between First Street and Second Street have number in the 100 series.”

Source:

http://whatacity.com/washington-d-c/376630-what-meant-word-unit-street-signs-washington-dc.html

Then scroll down toward the bottom of that web site’s page. (Best I could find in the middle of the night…)

Math Tourist said...

That still doesn't explain why the word "unit" rather than some other designation is used to represent that block of numbers.