The one thing visitors to the US need to remember, above all, is that American dollar notes (sorry, bills) often look identical. They're certainly all the same size and, until recently, exactly the same colour. The major differences are the denomination, the president and the scene depicted on the back of the notes.

Although this is currently true of the $1, $2 and $100 bills, since 2003 the remaining bills have undergone a major redesign to make them easier to differentiate, particularly for those with limited vision, and more difficult to forge.

In 1996, a new design for the $100 bills had been introduced in an attempt to reduce the chance of forgery, followed in 1998 by a new $20. However, these designs didn't go far enough, and it was decided to start a radical re-design of the dollar bills.

The $20 is the most frequently counterfeited, so it was the first to undergo the transformation, and in October 2003 it became the first American dollar bill in recent US history that wasn't just black and green. Instead, it has yellow and blue printing on it, and a distinct blue/green and peach-coloured background. And, like all subsequent redesigns, it used a colour-shifting ink for the denomination at the bottom right, which changes from copper to green depending on the angle at which it is viewed.

The $50 was the next to be redesigned. Introduced in September 2004, it has a distinct pale blue/red and peach-coloured background. Then came the new $10 bill, in March, 2006, in shades of orange, yellow and red.

The most recent (at the time of writing) is the new $5 bill. This was introduced in March, 2008, and is light purple in middle, changing to grey at the ends. The $100 bill will be redesigned in due course, but a date has not yet been set.

		2008
		2006
		2003
		2004

As you can see above, at long last these dollar bills look distinctive enough to be differentiated without having to look at the detail, particularly when looking at the edges of the bills in a stack (as shown by the comparison above).

Although the lower denominations still cause difficulties, a few years ago the US Treasury stated that they would not be redesigning the $1 and $2 bills. So, with the $2 bill not being particularly common, the $1 bill will be the only "old-style" paper money that visitors are likely to encounter as the new bills increase in circulation.

The table below shows the basic design features (which, despite the redesigns, haven't changed) of all the bills, which range from $1 in value right up to $100,000 (although the $100,000 bills were only ever used for internal government transactions). In 1969, the US Government stopped circulation of all banknotes over $100 in value and as these bills reach the Federal Reserve Bank they are withdrawn from circulation.

The $1m bill listed in the table is a myth, even though it is mentioned in some lists of US currency (although a series of such "One Million Dollar Special Issue" bills were produced as a work of art in the 1980s, and some fairly convincing novelty $1,000,000 bills have been produced over the years). In reality, the highest denomination ever produced was the $100,000 bill and this was only produced for internal government purposes for a period of about 3 weeks over the New Year period in 1934/5.

The $2 bill is a bit of a rarity, but they still represent about $1bn of currency in circulation.

Value	Front	Back	Comments
$1	George Washington (1st)	Great Seal of US	Dollar coins are also in circulation
$2	Thomas Jefferson (3rd)	Signing Declaration of Independence	Considered unlucky by some
$5	Abraham Lincoln (16th)	Lincoln Memorial	New design 2008
$10	Alexander Hamilton (Treasury Secretary)	US Treasury	New design 2006
$20	Andrew Jackson (7th)	The White House	Redesign 1998 New design 2003
$50	Ulysses S Grant (18th)	US Capitol
$100	Benjamin Franklin	Independence Hall	Redesign 1996
$500	William McKinley (25th)	design	ceased in 1969
$1000	Grover Cleveland (22nd & 24th)	design	ceased in 1969
$5000	James Madison (4th)	design	ceased in 1969
$10,000	Salmon P Chase (Associate Justice of the Supreme Court)	design	ceased in 1969
$100,000	Woodrow Wilson (28th)	design	used by government only
$1m			no such bill was ever issued