“Dear PoP,
Perhaps you or one of your readers has already posed this question, but I’m wondering if anyone out there can enlighten me as to why there isn’t a J st anywhere in DC? And for that matter, there is no 2-syllable street that begins with the letter J – at least not in NW on either side of the park. NE has Jackson St, but NW has no J streets until it gets up to the 3-syllable names (Jennifer, Jocelyn, Jefferson). WTF?”
The Washington Post has tackled this question a number of times. They explain that it was a myth that Pierre L’Enfant hated Chief Justice John Jay. The real reason is:
“Back in Colonial times, the letters I and J were written alike. (The Latin alphabet doesn’t even have a J.) There’s no J Street because the District’s designers didn’t want people to confuse it with I Street.”