Where is the series letter on a US silver certificate?

Normally the series letter on a bill is right after or underneath the bill's date. However, many bills don't have series letters:

First, series letters weren't used on bills until the late 1920s so if your bill is older than that it'll only have a date.

Second, the way series letters are put on bills isn't completely straightforward. When a new series date starts (more below) the first set of bills in that printing normally doesn't have a letter (but again, more below). When a change occurs to trigger a series letter, an A is added, then a B, etc. That means an A series is the second run, B is the third, and so on.

When do dates and letters change?Originally, series letters were changed only when a new Secretary of the Treasury or a new Treasurer was appointed, and a new date was used only a bill was redesigned. Unlike coins, the series date only indicates the first year of issue, not the date the bill was actually printed.

Because bills weren't redesigned very often in the 20th century the situation became almost ridiculous. For example the 1935 series of $1 bills was printed into the 1960s and letters got all the way up to H.

The policy changed in 1974 so a new date is used when a new Secretary of the Treasury takes office, and a new series letter is used when a new Treasurer is appointed. As a result, dates change much more frequently and series letters rarely go beyond A or B.

The new policy has had its share of anomalies, too. For example, because new $10 bills were printed only after a second treasurer was named in the first Bush administration, there were 1988A bills but no 1988s.

Other letters on US bills:A series letter isn't the same as the letter standing for the issuing Federal Reserve District, nor is it related to the letters indicating the bill's plate position when it was printed - these cause a lot of confusion.