There’s no L St. in Georgetown. You can walk straight from K St. to M St. without passing their middle sibling. And partially as a result of this, an odd numbering sequence reigns over south Georgetown. Some north-south streets have street addresses beginning with 1100, and some don’t. Here’s why:
Throughout DC, north-south streets are numbered according to the lettered cross streets. Thus the first block of, say, Fifth st. north of A St. is 0100. And once it crosses B St., the address numbers start with 0200. And so on.
The building numbers north of K St. in Georgetown are 1000. (K is the eleventh number, so you’d think the addresses north of it would be 1100, but because there’s no J street, there’s a shift after I St.) And the buildings’ addresses north of M St. start with 1200.
For most of the 19th century, Georgetown’s street names didn’t integrate with the rest of DC. There was no K St., M St., N St., etc. (They were Water St., Bridge/Falls St., and Gay/First St., respectively.) But in 1895, Georgetown’s street names were changed to be consistent with the rest of DC. But there was no east-west street that correlated with L St. The canal was in the way.
So there’s no L St. in Georgetown, but here’s the weird thing: for 29th and 30th St., the streets north of the canal are numbered as if there were an L St. In other words, buildings north of the canal on 29th St. have street addresses starting with 1100. (In truth, the only building on that block that has a 29th St. address is the old Bartleby Books building at 1132 29th St.)
It gets even weirder for 30th St. The buildings on the east side north of the canal have addresses beginning with 1100. But the buildings on the west side, however have addresses starting with 1000.
For Thomas Jefferson St., 31st St. and Wisconsin Ave., it’s like the west side of 30th: address numbers stay in the 1000s until they jump to the 1200s north of M St.
So why the difference?
GM queried Twitter and someone who would know the answer answered. Prior to the construction of the canal, there was a street that bisected 28th, 29th and 30th. It was called Needwood St., and part of it was still around in 1903, as you can see from this map:
(Supposedly an 1893 map would show it going further west, but GM couldn’t find a copy).
Homes north of Needwood were numbered as a new block. But since it didn’t go west of 30th (which was called Washington St. before the renaming) there wasn’t a similar street numbering scheme to the west. Because Needwood ended at 30th/Washington, they treat the east side as if it were a new block and the west side as if it weren’t. And that quirk was carried forward to today.
So there you have it. Because there’s no L St., there’s no 1100 block of Wisconsin. But because there once was a street sort of like L St., there is an 1100 block of 28th, 29th, and part of 30th.